RESULTS & DISCUSSION
4.6 Results of antibiotic sensitivity tests
A total of two isolates such as. E. coli, Salmonella spp. were subjected to antibiotic sensitivity assay because these two isolates have severe public health importance and cause different diseases. Besides, necessary media and reagents were available in the laboratory. The results of antibiotic sensitivity assay are presented below:
41 4.6.1 Antimicrobial profile of E. coli
Positive E. coli isolates were tested against 5 different antibiotics. Among them Gentamycin showed the highest susceptibility pattern followed by the Ciprofloxacin and Streptomycin in this study. Highest resistant pattern was showed by Tetracycline and then Ampicillin.
Table 10: Antimicrobial profile of E. coli Name of antibiotic
disc
Interpretation Number of Sensitivity
Percentage (%) Ciprofloxacin
N=80
S 52 65.00
I 28 35.00
R 0 0.00
Streptomycin N=80
S 50 62.50
I 18 22.50
R 12 15.00
Ampicillin N=80
S 0 0.00
I 5 6.25
R 75 93.75
Tetracycline N=80
S 0 0.00
I 0 0.00
R 80 100.00
Gentamycin N=80
S 75 93.75
I 5 6.25
R 0 0.00
Legends: R=Resistant, S=Sensitive, I=Intermediate.
Ciprofloxacin: R ( 20), I (16-21), S ( 31) Streptomycin: R ( 15), I (21-30), S ( 22) Ampicillin: R ( 12), I (13-19, S ( 20) Tetracycline: R ( 11), I (12-14), S ( 15) Gentamycin: R ( 12), I (13-14), S ( 15) *Diameter of zone of inhibition expressed in mm.
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Fig 11: Antibiogram of E. coli
Fig 12: Antibiotic sensitivity of E. coli
0 10 20 30 40 50 60 70 80 90 100
S I R S I R S I R S I R S I R
CIPROFLOXACIN STREPTOMYCIN AMPICILLIN TETRACYCLINE GENTAMYCIN Number of Sensitivity Percentage (%)
Tetracycline (R) Streptomycin(S) Gentamycin(S)
Ampicillin(R) Ciprofloxacin(S)
43 4.6.2 Antimicrobial profile of Salmonella spp.
Positive Salmonella isolates were tested against 5 different antibiotics. Among them Gentamycin showed the highest susceptibility pattern followed by Ciprofloxacin and Streptomycin. Highest resistant pattern was showed by Tetracycline and Ampicillin.
Table 11: Antimicrobial profile of Salmonella spp.
Name of antibiotic disc
Interpretation Number of Sensitivity
Percentage (%) Ciprofloxacin
N=88
S 65 73.86
I 17 19.25
R 6 6.89
Streptomycin N=88
S 30 34.00
I 42 47.82
R 16 18.18
Ampicillin N=88
S 0 0.00
I 0 0.00
R 88 100.00
Tetracycline N=88
S 0 0.00
I 0 0.00
R 88 100.00
Gentamycin N=88
S 70 79.54
I 18 20.46
R 0 0.00
Legends: R=Resistant, S=Sensitive, I=Intermediate.
Ciprofloxacin: R ( 20), I (16-21), S ( 31) Streptomycin: R ( 15), I (21-30), S ( 22) Ampicillin: R ( 12), I (13-19, S ( 20) Tetracycline: R ( 11), I (12-14), S ( 15) Gentamycin: R ( 12), I (13-14), S ( 15) *Diameter of zone of inhibition expressed in mm.
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Fig 13: Antibiogram of Salmonella spp.
Fig 14: Antibiotic Sensitivity Salmonella spp.
0 10 20 30 40 50 60 70 80 90 100
S I R S I R S I R S I R S I R
Ciprofloxacin Streptomycin Ampicillin Tetracycline Gentamycin Number of Sensitivity Percentage (%)
Tetracycline (R) Ciprofloxacin (S)
Ampicillin (R) Gentamycin (S) Streptomycin (I)
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Because of the rapid spread and emergence of antibiotic resistant bacteria and their resistance genes among humans, animals and the environment at global scale, antibiotic resistance is now considered as a one health challenge. Hospital waste water is a major source for antibiotic resistant bacteria that are of great public health concern. Most of the researches on AMR emphasized on human and animal and there is a lack in AMR situation in the waste water of hospitals in Sher-e-Bangla Nagar area.
One of the most alarming findings of this study is that all the isolates of E. coli and Salmonella spp. were found Multi Drug Resistant (MDR) to tetracycline and ampicillin mostly.
Tetracycline is used widely (Hassan et al., 2015) in Bangladesh. Long time wide spread use of tetracycline in veterinary and human medicine could be lined with this resistant result against tetracycline. Peak et al. (2007) and Huang et al. (2019) also found tetracycline resistance genes in various types of waste water. It was also important to note that isolates of E. coli and Salmonella spp. in this study were found to be resistant in nature. For example, waste water is resistant against tetracycline, ampicillin, ciprofloxacin and streptomycin. Rashid et al. (2015) observed the presence of MDR E. coli in various aquatic sources in Bangladesh earlier. Like these evidences, we found both resistant and sensitive bacteria from hospitals. Waste water containing E. coli where tetracycline was resistant (100%). Ampicillin (93.75%) was close to tetracycline considering resistant. On the other hand, gentamycin (93.75%) was more sensitive than ciprofloxacin (73.86%) and streptomycin is intermediate (62.5%). Waste water containing Salmonella spp where tetracycline and ampicillin are100% resistant. On the other hand, gentamycin (79.54%) was more sensitive than ciprofloxacin (65%) and streptomycin (47.82%) is sensitive. In Bangladesh, Zahid et al. (2009) went through an investigation on the occurrence of multiple ARB and their chromosomal determinants in surface water. From 147 samples, they isolated 103 bacterial species where 65% were E. coli including isolates resistant to tetracycline.
While Siddiqui et al. (2015) showed presence of antibiotic resistant Salmonella spp. in hospital waste and many of which truly ended up in the sewage in Bangladesh. Same type of result was also shown by another group (Ashfaq KMA, Pijush S et al,.2013) where Ampicillin was the antibiotic to which highest number of resistant bacteria (93.1%) was found. In the study, Salmonella spp. were 100% resistant to Ampicillin by E. coli (75%). Among all isolates of Gram-negative bacteria, 75% of isolates were found to be resistant to Amoxicillin followed by
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Ampicillin (63.5%), Chloramphenicol (30.7%), Gentamycin (28.8%) and least being Ciprofloxacin (23.1%). Previously, similar Ciprofloxacin resistant E. coli was found and characterized from the Chittagong Medical College Hospital & Dhaka Medical college Hospital liquid waste. Nahar et al. (2019) found E. coli were resistant streptomycin (16.6%) and ampicillin (97.2%) while Salmonella spp. to ciprofloxacin (07.1%), streptomycin (19.1%) and ampicillin (100%) by observing 47 samples from sewage water in Mymensingh. According to Alam et al. (2013) examined sixty-nine isolates for antibiotic sensitivity where 73.9% strains were resistant to ampicillin. However, resistance to streptomycin, tetracycline, and doxycycline was recorded in less than 13% of the strains. Some variations of antibiotic sensitivity with others were also observed. Most of the hospitals of abroad used ETP strictly which is completely rare in mentioned hospital. Some results were recorded as different from others mostly abroad because of indiscriminate use of antibiotics in Bangladesh where there had a lack of proper law and order to control excess use of antibiotics. The diagnosis process was not developed and the hygenic measures were taken in the mentioned hospital like others in the world. Besides, as we completed this research amid of covid19 with some limitations and collected water from different points of hospitals, some data were not similar but close to previous research. So, the present study findings support maximum of the earlier observations.
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