Prospective Study on Bacterial Isolates with their Antibiotic Susceptibility Pattern from Pus ( Wound ) Sample in Kathmandu Model Hospital

Background: Wound infection is a very common infection throughout the world and is causing a great fear in developing countries like Nepal. The present study was carried out in Kathmandu Model Hospital with an aim to find out the bacteriological episodes in pus samples in relation to age and sex, Antibiotic Susceptibility Testing (AST) and drug resistance pattern among the isolates. Methodology: A total of 157 pus samples included in the study were processed in the Microbiology laboratory of Kathmandu Model Hospital using standard microbiological techniques. Identification of organisms was done on the basis of microscopy, colony morphology, and biochemical tests. The antibiotic sensitivity testing of all isolates was performed by Kirby Bauer’s disc diffusion method on Muller Hinton agar and interpreted as per CLSI guidelines. Results: Analysis of 157 pus samples showed (93, 59.24%) culture positive cases with (63, 67.74%) Multi Drug Resistance (MDR) isolates. Age group (21-30) was found to be the most vulnerable age group. Staphylococcus aureus (29, 28.71%) was the predominant organism isolated among gram positive bacteria and Escherichia coli (26, 25.74%) among gram negative bacteria. Gentamycin was the most sensitive antibiotic among gram positive bacteria whereas Amikacin being the most sensitive Antibiotic among gram negative bacteria. Conclusion: Antibiograms of isolates can serve as a tool for physicians to start an empirical treatment and minimize the drug resistance problem.


BACKGROUND
Wound is defined as break in the normal continuity of the skin or a body structure caused by injury [1].Wound infection can be defined as the presence of organisms in a wound that are multiplying and eluciting a host reaction.In laboratory terms, it is often defined as an organism counts of greater that 10 5 gram of tissue [2].Surgical wound infection, acute soft tissue infection, bite wound infection, burn wound infection, pyogenic wound infection, leg and decubitus (pressure) ulcer infections are the categories of wound infection [3].
Infection can occur at an incision site within 30 days of an operation, but wounds that are closed and primarily healed does not necessarily mean infected [  Enterobacter aerogens each (1, 1.6%) respectively (Fig.

COMPETING INTERESTS
We declare that we don't have competing of interest.

AUTHORS' CONTRIBUTIONS
PC, CS, SRP performed the laboratory experiments and data collection.SK, BS supervised and guided in the research.PC, BT performed statistical analysis, conceived part of this study and revised the manuscript.All authors read and approved the final manuscript.
4]. Pre-existing illness, length of operation, wound class, and wound contamination are the predisposing factor for wound infection [5].Surgical wound and skin infections accounts for 70-80% mortality.It leads to almost one third of the hospital acquired infection among surgical patients [6].People in Nepal are generally prone to agricultural wounds, traffic accidents and domestic injuries.People are not aware and knowledgeable about the prevention of injuries and disabilities.It may lead to complications due to poor management of wounds at the initial stage.Absence of facilities in the district and peripheral hospitals along with traditional unscientific household practices and Prospective Study on Bacterial Isolates with their Antibiotic Susceptibility Pattern from Pus (Wound) Sample in Kathmandu Model Hospital Copyright © 2015 International Journal of Medicine & Biomedical sciences.All right Reserved.lack of safety system result in wound infection.In Nepal, MDR pathogens are more prevalent because of the imprudent use of antibiotics and people failing to take the full course of treatment.The important factors associated with resistant bacteria are poor resources for infection control, lack of manpower trained in controlling infection in hospital and poor hospital management system [7].The present study was done to find the resistance pattern of isolates to different group of Antibiotics.METHODOLOGY This study was carried out from July 25, 2010 to October 26, 2010 in the Microbiology laboratory of Kathmandu Model Hospital thereby covering a total period of 3 months.A total of 157 pus samples were collected from the patients ranging in age from 3 months to 84 years.Pus samples were collected on a sterile cotton swab or aspirated in syringe and labeled with date, time, and the patient's name, age and sex.For laboratory investigation, two pus swabs were collected; one for the direct smears preparation and the other one for culture.Macroscopic and microscopic observations were noted.Samples were inoculated on to Blood agar (BA), MacConkey agar (MA) and were incubated at 37°C for 24 hrs to 48 hrs in aerobic condition; the study did not include anaerobic bacteria culture.After overnight incubation, the culture plates were examined for bacterial growth and identified using standard microbiological techniques which included colony characteristics, staining reactions and biochemical reactions such as catalase, coagulase, indole, methyl red, Voges-Proskauer, citrate, urease, Triple Sugar Iron Agar (TSI) and Oxidase test.The antibiotic sensitivity testing of all isolates was performed by Kirby Bauer's disc diffusion method on Muller Hinton agar (MHA) and interpreted as per CLSI guidelines.Quality control is considered as one of the important factor for the correct result interpretation [8].Standard strains taken for quality control was Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) [9].

Fig. 2
Fig. 2 Distribution of organisms isolated with MDR cases wounds and hygienic practices help to minimize the incidence of the wound infections.Frequent and timely conversation between the microbiologist and wound care practiconers also plays a major role in limiting the wound infection in hospitals.Similarly, the antimicrobial susceptibility testing result suggests that some antibiotics would have very limited usefulness for the prophylaxis or the empirical treatment of wound infection.The result might serve as a foundation for establishing empiric therapeutic approaches for the management of such infections in Kathmandu Model Hospital and other Health care institutions of Nepal.

Table 2 : Antibiotic susceptibility pattern of Gram positive isolates
Copyright © 2015 International Journal of Medicine & Biomedical sciences.All right Reserved.

Table 3 : Antibiotic susceptibility pattern of Gram negative isolates ANTIBIOTIC Sensitive
from 3 months to 84 years with age group 21-30 years being the most affected age group which agrees with the studies done by researchers in Nepal, Parajuli et al, (1997),

Table 5 : Antibiotic Susceptibility pattern for isolates of Escherichia coli
et al, (1998), Karkee et al, (2008), and Kumari et al, (2008).Since the age group 21-30 are the most active age group and they are mostly involved in outdoor activity they might be the most affected age group.
Copyright © 2015 International Journal of Medicine & Biomedical sciences.All right Reserved.Tuladhar et al, (1995) and Kumari et al, (2008), their study showed that gram negative bacteria were isolated more compared to the gram positive bacteria.Shrestha et al, (2010) showed that Gram negative bacilli (52.3%) had a slightly higher frequency than Gram positive cocci.(2007).On the other hand, the study done by et al, (2010) showed that Coagulase Negative Staphylococci (CoNS) was the predominant organism isolated and S.

International Journal of Medicine Biomedical Sciences. 2015; 1(1):15-22 www.intlmedbio.com 20
Copyright © 2015 International Journal of Medicine & Biomedical sciences.All right Reserved.most sensitive antibiotic and in case of kumari et al, CONCLUSION Though wound infection is a non eradicable problem, but preventive measures, good disinfection and treatment protocols, clean surgical procedures, proper care of showed Amikacin (77.8% and 94.38%) was the most sensitive antibiotic for E. coli respectively.