Microbial Analysis of Urine and Antibiotic Sensitivity Pattern of Isolated Infectious Agents from Patients Suffering in Urinary Tract Infection ()
1. Introduction
A urinary tract infection (UTI) (also known as acute cystitis or bladder infection) is an infection that affects the urinary tract. When it affects the lower urinary tract, it is known as a simple cystitis (a bladder infection) and when it affects the upper urinary tract, it is known as pyelonephritis (a kidney infection). Symptoms from a lower urinary tract include painful urination and either frequent urination or urge to urinate (or both), while those of pyelonephritis include fever and flank pain in addition to the symptoms of a lower UTI. In the elderly and the very young, symptoms may be vague or nonspecific. The main causal agent of both types is Escherichia coli, however other bacteria, viruses or fungi may rarely be the cause.
Bacterial infections of the urinary tract are the most common cause of both community acquired and nosocomial infections for patients admitted to hospitals in the United States. It is distressing and occasionally life threatening. However, the prognosis and management of urinary tract infections depend on the site of infection and any predisposing factors. It has been estimated that about six million patients visit outpatient departments and about 300,000 are treated in the wards every year for UTI worldwide [1]. With the constantly shifting trends in drug resistance, antibiotic options, and multiplying microorganisms, UTI implies both microbial colonization of the urine and invasion of the lower or upper urinary tract by microorganisms [2]. The traditional guideline that urine containing more than 100,000 bacteria/ ml is responsible for an incidence of UTI has been modified currently. Counting as low as 1000/ml of any single bacterial type or as few as 100/ml of coliforms such as E. coli, are now considered an indication of significant infection, especially if leukocytes appear in the urine [3] [4].
Uropathogens differ in terms of the virulence factors and pathogenic mechanisms that allow them to colonize and infect the urinary tract. Gram negative bacteria cause 80% - 85% whereas Gram positives cause 15% - 20% of the cases. Common Gram-negative species include E. coli, Klebsiella, Proteus, Enterobacter, Pseudomonas, and Serratia spp. and Gram-positive organisms, including group B streptococci, Enterococcus spp., and Staphylococcus aureus and Staphylococcus saprophyticus, have also been frequently isolated in both urban and rural areas [4] [5].
The incidence of UTI is greater in women (20%) as compared to men, which may be either due to anatomical predisposition or urothelial mucosa adherence to the mucopolysaccharide lining or other host factors and vice versa [5] [6]. Most UTIs are preceded by an association of sexual activity with colonization and vaginal acquisition, pregnancy and obstruction which are responsible for the increasing frequency of UTI in females. Though UTI susceptibility may occur to anybody, the prevalence of infection normally differs with age, sex and certain predisposing factors such as diabetes, pregnancy, and impaired voiding of the bladders [7].
For this reason, the present study aimed to evaluate the prevalence of uropathogens and observe the patterns of antibiotics against uropathogens in different groups ages of both genders.
2. Materials and Methods
2.1. Ethical Concern
The protocol was approved by the Ethical Review Committee of the National Institute of Neurosciences & Hospital, Dhaka, Bangladesh.
2.2. Study Area and Population
The study was carried out at the National Institute of Neurosciences & Hospital, Dhaka, Bangladesh from October, 2016 to March, 2017. This retrospective analysis included 200 consecutively collected midstream and/or catheter-catch urine samples from clinically suspected patients of UTI of different ages and sexes who were admitted to the hospital.
2.3. Sample Collection
The clean catch midstream urine samples were collected and transported from clinically suspected patients following CLSI guidelines 10. The samples were taken in clean, sterile 50 mL screw-capped amber colored universal containers with an opening of at least 4 cm. The consent was obtained from all patients by verbal information, and they were advised to follow the proper aseptic collection procedure for urine prior to collection. All the samples were collected before the start of antibiotic therapy.
2.4. Chemicals and Media
Several cultural media were used in this study. These are MacConkey’s Agar, Muellar Hinton and Blood Agar.
2.5. Isolation and Identification of Uropathogens
Bacterial identification was done by phenotypic examination of the organisms on culture media followed by biochemical tests specific for uropathogens. One loop full of urine samples was inoculated onto sterilized and solidified Blood agar and MacConkey agar media followed by incubation at 37˚C for 24 h aerobically. After incubation, the numbers of bacterial colonies were counted.
2.6. Antibiogram
Mueller–Hinton agar was used for antimicrobial susceptibility testing (AST) following Kirby-Bauer disc diffusion method, against a panel of 13 antibiotics (Biomaxima, Poland) including Azythromycin, Ciprofloxacin, Ceftriaxone, Ceftazidime, Cefixim, Imipenem, Cefuroxime, Amoxycillin, Gentamicin, Doxycyclin, Co-trimoxazole, Nitrofurantion, Meropenem as per the Clinical Laboratory Standard Institute (CLSI) guidelines 13, susceptibility was noted as sensitive, resistant and intermediate based on the diameter of zone of inhibition.
2.7. Data Analysis
Data obtained were analyzed by SPSS version 20 and Excel 2016. The percentage of frequencies was generated for categorical variables such as rate of isolation, type of bacteria, rate of antibiotic sensitivity, resistance, and intermediate of the organisms.
3. Result & Discussion
A total of 200 patients of UTI of either sex (male-60 and female-140) with the respective male ratio of 30% and female 70% provided urine specimens (see Tables 1-9).
Table 1. Total number of specimens 200 (N).
Criterion of specimen |
Number |
Specimens showing positive case |
45 |
Percentage of positive culture for urinary pathogen |
22.50% |
Specimens showing negative case |
155 |
Percentage of negative culture for urinary pathogen |
77.5% |
We found 45 cases positive among a total of 200 cases in this study.
Table 2. Sample size and distribution: The total number of respondents sample was 200.
Sample study |
Number |
Patient attending |
200 |
Total Sample |
200 |
Sample collect from adult male |
45 |
Sample collect from adult female |
100 |
Sample collect from male child |
15 |
Sample collect from female child |
40 |
Negative case in adult male |
38 |
Positive case in adult male |
07 |
Negative case in adult female |
70 |
Positive case in adult female |
30 |
Negative case in male child |
13 |
Positive case in male child |
02 |
Negative case in female child |
34 |
Positive case in female child |
06 |
Total negative case |
155 |
Total positive case |
45 |
The following type of distribution was done according to age and sex in this study.
Table 3. Age and sex distribution of UTI patient.
Sl. No |
Age |
Total patient |
Male |
Percentage |
Female |
Percentage |
1 |
0 - 10 |
28 |
07 |
25% |
21 |
75% |
2 |
11 - 20 |
18 |
06 |
33.33% |
12 |
66.66% |
3 |
21 - 30 |
25 |
09 |
36% |
16 |
64% |
4 |
31 - 40 |
36 |
10 |
27.77% |
26 |
72.235 |
5 |
41 - 50 |
32 |
11 |
34.37% |
21 |
65.63% |
6 |
51 - 60 |
15 |
06 |
40% |
09 |
60% |
7 |
61 - 70 |
35 |
09 |
25.72% |
26 |
74.28% |
9 |
71 to above |
11 |
03 |
27.28% |
08 |
72.72% |
We found 41 - 50 and 31 - 40 aged people among male are more infected compared to other raged people and 31 - 40, 0 - 10, 41 - 50 aged people among female are more infected compared to other people in this study. But in some other studies, among positive cases, 5.77% cases were in people aged 0 - 12 years old, 36.54% cases were in between 13 - 24 years, 32.7% were in between 25 - 36 years, 13.46% cases were 37 - 48 years, 7.70% cases were 49 - 60 years, 3.83% cases were 61 - 72 years of age [8].
Table 4. Infectious agent and their number with percentage (N = 200).
Finding infectious agent of the study |
Number of isolation |
Percentage |
E. Coli |
30 |
15% |
Staphylococcus saprophyticus |
7 |
3.5% |
Staphylococcus aureus |
5 |
2.5% |
Pseudomonas spp |
2 |
1.0% |
Enterococcus spp. |
1 |
0.5% |
We found E. coli was most prominent in this study but Staphylococcus saprophyticus, Staphylococcus aureus, Pseudomonas spp and Enterococcus spp was also found in the observed specimens. But in some other studies, out of 100 urine samples 60 were positive for pathogenic organisms. Escherichia coli was isolated in 68.3% of the positive samples, followed by Klebsiella sp 21.6%, Pseudomonas sp 5% Proteus sp 3.3% Staph. aureus 1.66% [7].
Table 5. Antibiotic sensitivity pattern of E. Coli.
Name of antibiotic |
Sensitivity |
Percentage |
Resistance |
Percentage |
Azithromycin |
24 |
80% |
6 |
20% |
Ciprofloxacin |
20 |
66.6% |
10 |
33.3% |
Ceftriaxone |
24 |
80% |
6 |
20% |
Ceftazidime |
21 |
70% |
9 |
30% |
Cefixim |
19 |
63.3% |
11 |
36.6% |
Imipenem |
18 |
60% |
12 |
40% |
Cefuroxime |
22 |
73.3% |
8 |
26.6% |
Amoxycillin |
19 |
63.3% |
11 |
36.6% |
Gentamicin |
21 |
70% |
9 |
30% |
Doxycyclin |
22 |
73.3% |
8 |
26.6% |
Co-trimoxazole |
20 |
66.6% |
10 |
33.3% |
Nitrofurantion |
17 |
56.6% |
13 |
43.3% |
Meropenem |
23 |
76.6% |
7 |
23.3% |
Azithromycin, Ceftriaxone showed highest sensitivity against E. coli but Nitrofuranton, Gentamicin and Cefixime showed comparatively lower sensitivity against E. coli.
Table 6. Antibiotic sensitivity pattern of Staphylococcus saprophyticus.
Name of antibiotic |
Sensitivity |
Percentage |
Resistance |
Percentage |
Azithromycin |
4 |
57.1 |
3 |
42.8% |
Ciprofloxacin |
3 |
42.8% |
4 |
57.1 |
Ceftriaxone |
5 |
71.4% |
2 |
28.5% |
Ceftazidime |
2 |
28.5% |
5 |
71.4% |
Cefixim |
3 |
42.8% |
4 |
57.1 |
Imipenem |
6 |
85.7% |
1 |
14.2% |
Cefuroxime |
7 |
100% |
0 |
- |
Amoxycillin |
3 |
42.8% |
4 |
57.1 |
Gentamicin |
4 |
57.1 |
3 |
42.8% |
Doxycyclin |
5 |
71.4% |
2 |
28.5% |
Co-trimoxazole |
3 |
42.8% |
4 |
57.1 |
Nitrofurantion |
7 |
100% |
0 |
- |
Meropenem |
5 |
71.4% |
2 |
28.5% |
Nitrofuranton, and Cefurixime showed the highest sensitivity against S. saprophyticus but Ceftazidime showed lowest sensitivity against S. saprophyticus.
Table 7. Antibiotic sensitivity pattern of Staphylococcus aureus.
Name of antibiotic |
Sensitivity |
Percentage |
Resistance |
Percentage |
Azithromycin |
4 |
80% |
1 |
20% |
Ciprofloxacin |
4 |
80% |
1 |
20% |
Ceftriaxone |
3 |
60% |
2 |
40% |
Ceftazidime |
3 |
60% |
2 |
40% |
Imipenem |
4 |
80% |
1 |
20% |
Cefuroxime |
3 |
60% |
2 |
40% |
Amoxycillin |
3 |
60% |
2 |
40% |
Gentamicin |
3 |
60% |
2 |
40% |
Doxycyclin |
4 |
80% |
1 |
20% |
Co-trimoxazole |
4 |
80% |
1 |
20% |
Nitrofurantion |
3 |
60% |
2 |
40% |
Meropenem |
5 |
100% |
0 |
- |
Meropenem showed highest sensitivity against S. aureus but Ceftriaxone, Ceftazidime, Cefurixime, Amoxyxillin, Gentamicin and Nitrofuranton showed comparatively lower sensitivity against S. aureus.
Table 8. Antibiotic sensitivity pattern of Pseudomonas spp.
Name of antibiotic |
Sensitivity |
Percentage |
Resistance |
Percentage |
Azithromycin |
2 |
100% |
- |
- |
Ciprofloxacin |
2 |
100% |
- |
- |
Ceftriaxone |
1 |
50% |
1 |
50% |
Ceftazidime |
1 |
50% |
1 |
50% |
Imipenem |
2 |
100% |
- |
- |
Cefuroxime |
1 |
50% |
1 |
50% |
Amoxycillin |
1 |
50% |
1 |
50% |
Gentamicin |
1 |
50% |
1 |
50% |
Doxycyclin |
2 |
100% |
- |
- |
Co-trimoxazole |
2 |
100% |
- |
- |
Nitrofurantion |
1 |
50% |
1 |
50% |
Meropenem |
2 |
100% |
- |
- |
Azithromycin, Ciprofloxacin, Imupenem, Doxycyclin, Co-trimoxazole and Meropenem showed highest sensitivity against Pseudomonas spp. but Nitrofuranton, Gentamicin, Amoxycillin, Cefurixime, Ceftazidime and Ceftriaxone showed comparatively lower sensitivity against Pseudomonas spp.
Table 9. Antibiotic sensitivity pattern of Enterococcus Spp.
Name of antibiotic |
Sensitivity |
Percentage |
Resistance |
Percentage |
Azithromycin |
_ |
_ |
1 |
100% |
Ciprofloxacin |
1 |
100% |
_ |
_ |
Ceftazidime |
1 |
100% |
_ |
_ |
Cefixime |
_ |
_ |
1 |
100% |
Imipenem |
1 |
100% |
_ |
_ |
Amoxycillin |
_ |
_ |
1 |
100% |
Gentamicin |
1 |
100% |
_ |
_ |
Doxycyclin |
1 |
100% |
_ |
_ |
Co-trimoxazole |
_ |
_ |
1 |
100% |
Nitrofurantion |
1 |
100% |
_ |
_ |
Meropenem |
1 |
100% |
_ |
_ |
All the antibiotics used showed 100% sensitivity against Enterococcus spp.
4. Conclusions
The present study concluded that the incidence of UTI is higher in females than males. Of course, this is also a foregone conclusion. The study found that Gram negative bacteria such as E. coli, Pseudomonas and Gram positive bacteria such as staphylococcus saprophyticus and staphylococcus aureus are the more common etiological agents for UTI in female subjects and in case of male patients. E. coli is found to be a principal etiological agent of UTI in this study.
Azithromycin and ceftriaxone showed the highest sensitivity against E. coli but Nitrofuranton, Gentamicin and Cefixime showed comparatively lower sensitivity against E. coli. Nitrofuranton and Cefurixime showed the highest sensitivity against S. saprophyticus but Ceftazidime showed the lowest sensitivity against S. saprophyticus. Meropenem showed the highest sensitivity against S. aureus but Ceftriaxone, Ceftazidime, Cefurixime, Amoxyxillin, Gentamicin and Nitrofuranton showed comparatively lower sensitivity against S. aureus. Azithromycin, Ciprofloxacin, Imupenem, Doxycyclin, Co-trimoxazole and Meropenem showed the highest sensitivity against Pseudomonas spp. but Nitrofuranton, Gentamicin, Amoxycillin, Cefurixime, Ceftazidime and Ceftriaxone showed comparatively lower sensitivity against Pseudomonas spp. All the antibiotics used showed 100% sensitivity against Enterococcus spp.
This phenomenon has arisen due to the indiscriminate use of antibiotics. This is due to the fact that even when no antibiotics are needed, they are given. Here, people can buy antibiotics without any prescription, take them for a few days, and then stop. No proper dose or duration of treatment is followed. All these have produced resistance to the antibiotics by the causative agents of UTI. The etiological agents of UTI and their sensitivity patterns vary between health institutions and different seasons, even within the same area. Therefore, we suggest that each health institution should determine the causative agents of UTI and their susceptibility to guide the management of UTI.
Acknowledgements
We acknowledge the stuff of the National Institute of Neuroscience & Hospital, Agargaon, Dhaka, Microbiology laboratory for their cooperation during laboratory testing and data collection.