Evaluation of the Gram-Negative Bacilli Causing Surgical-Site Infections and their Sensitivity to Antibiotics in Al- Mowasat Hospital, Damascus, Syria
Rana Ahmad
Department of Microbiology and Laboratory, faculty of Medicine, Al-Andalus university, Tartous, Syria.
*Corresponding Author E-mail: mansouroussama@yahoo.fr
ABSTRACT:
A Surgical-Site Infection (SSI) is an infection that occurs at a surgical cut within 30 days of a surgical operation. It is considered a major health issue in hospitals associated with high levels of morbidity and mortality. The infections caused by Gram-Negative Bacilli are main challenges to patients' health, because of high percentage of antibiotics resistance. This study aims to evaluate the incidence of SSIs in emergency surgical operations department, the epidemiology of Gram-Negative Bacilli in SSIs and their sensitivity to antibiotics. A total of 466 swab samples were taken from patients who had undergone surgical operations. Swabs were collected from the surgical incision or around it between December 2015 and March 2016. The results show the majority of bacterial isolates that cause the SSIs were Gram-Negative Bacilli (56%), while the Gram-Positive Cocci formed 44%, the predominant isolate was staphylococcus aureus (26/44) (59%) and the most commonly isolated Gram-Negative Bacilli were pseudomonas aeruginosa (22/56) (39.3%), followed by E.coli (14/56) (25%) and klebsiella (8/56) (14.4%). The most effective drugs were Imipenem and Meropenem followed by Amikacin.
KEYWORDS: Surgical-Site Infection, Gram-Negative Bacteria, Antimicrobial Sensitivity.
INTRODUCTION:
A Surgical-Site Infection (SSI) is an infection that occurs at a surgical cut within 30 days of a surgical operation (1,2) According to the Center for Disease Control and Prevention CDC, incisional SSIs are classified into three categories: superficial incisional surgical site infection, deep incisional surgical site infection and organ- space surgical site infection.(3) Despite the prevention strategies such as sterilization methods, SSIs are the most commonly reported nosocomial infections.(3,4) the incidence of SSIs in patients with hospital-acquired infections is about 14-20%. (5, 6) They are considered a major health issue in hospitals associated with prolonged hospital stay, and increasing the medical cost. (2)
Most SSIs are caused by bacteria, the pathogens isolated dependency on surgical procedure, susceptible host and etiology agents. (7,8) Many microbiological studies have shown that the most pathogen isolated from SSIs is Staphylococcus, but in the recent years there has been a rising prevalence of Gram-Negative Bacilli especially Pseudomonas, E. coli, Klebsiella as a cause of SSIs.(8) Infections caused by Gram-Negative Bacilli are a major challenge to patients' health, due to the high rate of anti-microbial resistance.(9) In Syria, no information is available on the prevalence of organisms especially Gram-Negative Bacilli that cause SSIs in surgery facilities. The current study aims to evaluate the incidence of SSIs in the facilities of emergency surgical operations, epidemiology of Gram-Negative Bacilli in SSIs and their sensitivity to antibiotics.
MATERIALS AND METHODS:
Sample collection:
A cross-sectional study design was conducted in the Department of General Surgery in Al-Mowasat Hospital in Damascus, between December 2015 and March 2016. A total of 466 swab samples were collected from patients who had undergone surgical operations. Swabs were collected from the surgical incision or around it. Personal information of all patients remains confidential. Permission from the Educational Hospitals Ethics Committee was obtained before the start of this study.
Bacteriological isolation:
the bacteriological identification was performed in the microbiology laboratory of Al-Mowasat Hospital. The swabs were immersed in Tioglycolate transport medium (CONDA, Spain), then cultured on Blood Agar (Liofilchem®, Italy) and Eosin- Methylen Blue Agar (Liofilchem®, Italy), the culture plates were incubated at 37ºc for 24 hours. The bacteria grown were identified by using conventional protocol including Gram stain on direct smear, colony morphology, biochemical tests (catalase test, oxidase test, coagulase test). Automatic device (BD Phoenix System) was used to confirm the isolates.
Antimicrobial Sensitivity Tests:
Antimicrobial Sensitivity was determined by disk diffusion method on Mueller Hinton Agar (CONDA, Spain), (Kirby-Bauer Antibiotic test), 13 antibiotic disks used were: Ciprofloxacin (30 µg\disk), gentamycin (30 µg\disk), ampicillin (25 µg\disk), imipenem (10 µg\disk), cefepime (30 µg\disk), clotrimoxazol (30 µg\disk), meropenem (10 µg\disk), amikacin (30 µg\disk), ceftazidime (30 µg\disk), cefotaxime (30 µg\disk), cefuroxime (30 µg\disk), cefoxitin (30 µg\disk), azatreonam (30 µg\disk).
RESULTS:
This study included 466 patients who had surgical operations, between December 2015 and March 2016. The aim was to evaluate the prevalence of Gram-Negative infections in the surgical operation site. There were 100 patients (21.5%) suffering from infections in surgical incision. The gender distribution was 60 male patients (60%) and 40 female patients (40%) (table 2). The results show that the majority of bacterial isolates that cause the SSIs was Gram-Negative Bacilli (56%), while the Gram-Positive Cocci formed 44% (table 3). Table 4 presents the distribution of Gram-Positive Cocci and gram negative bacilli, the predominant isolate was staphylococcus aureus (26/44) (59%) and the most commonly isolated Gram-Negative Bacilli were pseudomonas aeruginosa (22/56) (39.3%), followed by E.coli (14/56) (25%) and klebsiella (8/56) (14.4%). Two out of three swab samples which were collected from operation tables of emergency operation rooms were S. aureus. Overall the Gram- Negative Bacilli sensitivity to antibiotics is shown in table 5.
Table 1: number of patients who suffered from infection
Whole number (466) |
Number |
% |
Infections |
100 |
21.5 |
Steriles |
366 |
78.5 |
Table 2 : total distribution of patients according to gender
Gender |
Number |
% |
Male |
60 |
60 |
Female |
40 |
40 |
Total |
100 |
100 |
Table 3: total distribution of isolates according to gram stain
Isolates |
Number |
% |
Gram-positive cocci |
44 |
44 |
Gram- negative bacilli |
56 |
56 |
Total |
100 |
100 |
Table 4: frequency of Gram-Negative Bacilli from 100 patients with SSIs
gram negative bacilli |
Number |
% |
Pseudomonas aeruginosa |
22 |
39.3 |
E.coli |
14 |
25 |
Klebsiella pneumonia |
8 |
14.4 |
Proteus |
6 |
10.6 |
Enterobacter |
3 |
5.3 |
Shegilla |
2 |
3.6 |
Serretia |
1 |
1.8 |
Total |
56 |
100 |
Table 5 antibiotics resistance pattern for gram negative bacilli *
|
P. aeruginosa (N=22) |
E.coli (N=14) |
Klebsiella (N=8) |
Proteus (N=6) |
Enterobacter (N=3) |
Shegilla (N=2) |
Serretia (N=1) |
Clotrimoxazole |
20 (91) |
11(79) |
4(50) |
6(83) |
3(100) |
0(0) |
1(100) |
Meropenem |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
Imipenem |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
Gentamycin |
16(73) |
9(64) |
6(75) |
4(67) |
0(0 |
0(0) |
0(0) |
Ciprofloxacin |
14(64) |
10(72) |
4(50) |
0(0) |
0(0) |
0(0) |
0(0) |
Ceforoxim |
22(100) |
12(86) |
8(100) |
0(0) |
3(100) |
1(50) |
0(0) |
Cetazidime |
14(64) |
14(100) |
8(100) |
6(100) |
3(100) |
2(100) |
0(0) |
Cefoxitin |
22(100) |
3(21) |
2(25) |
0(0) |
0(0) |
0(0) |
1(100) |
Cefotaxime |
22(100) |
12(86) |
6(75) |
0(0) |
0(0) |
0(0) |
1(100) |
Cefepime |
18(82) |
12(86) |
6(75) |
0(0) |
0(0) |
0(0) |
0(0) |
Azatereonam |
20(91) |
14(100) |
8(100) |
6(100) |
2(66.6) |
0(0) |
1(100) |
Ampicillin |
22(100) |
14(100) |
8(100) |
4(67) |
3(100) |
2(100) |
1(100) |
Amikacin |
6(27) |
1(7) |
0(0) |
0(0) |
0(0) |
0(0) |
0(0) |
*= NO(%)
DISCUSSION:
Nosocomial infections are a major problem for health care centers All over the world. Surgical site infections still form very serious problems that can threaten patients’ lives, lead to prolonged hospital stay, and increase hospitalization and treatment cost (10,11). The rate of SSIs has been reported to be 2.5-41.9%. (12,13) Gram-Negative Bacilli remains one of the most important challenges that obstructs patients' health because they have developed resistance to several types of antibiotics (11). This investigation was conducted to evaluate the Gram-Negative Bacilli incidence in post-operative-wound infections in Syria. Among 466 patients who had surgical operations, bacterial organisms were isolated from 100 patients (21.5%). By comparing the current study results with the results of other studies around the world, it has shown a significant variation in the rate of SSIs, such as Malik, S. et al 2011 (12), Dessalegn, L. et al 2014 (14), Negi, V. et al 2015 (8), and Bajaj, A. et al 2017 (15) (96.03%, 71.1%, 17.8%, 6.97%) respectively. In addition, the results of the studies that were conducted in USA and in Europe show very low rate of SSIs (2-5%) (16). This variation maybe due to lack of attention to infection control procedures or perhaps due to the patient's immune disorder. The results of this study showed high rate of SSIs in male patients (60%) compared to female patients (40%); this is similar to the results of Malik, S. et al 2011 (51.9% male, 48.1% female) (12), and Adwan, Gh. et al 2016 (63.3% male, 37.4% female) (7) and Dessalegn, L. et al 2014 (80.2% male, 57.7% female) (14). By contrast, other studies showed the rate of SSIs higher in females than in males (17,18).
Gram-Negative Bacilli is comprised of 56% of all bacterial isolates in SSIs. The most common pathogen is pseudomonas aeruginosa (39.3%) followed by E.coli (25%) and klebsiella (14.4%). Similar results have been reported in studies conducted by Masaadeh, Ha. et al 2009 (27.8% for pseudomonas and 15.6% for E.coli) (19) and Ranjan, KP. et al 2011 (29.6% for pseudomonas and 20.3% for E.coli) (20), Malik, S. et al 2011 (17.8% for pseudomonas and 14.4% for E.coli) (12) and Bajaj, A. et al 2017 (26% for pseudomonas and 7.56% for E.coli) (15). These results conducted with other studies (7,8,14,17,18) that have reported E.coli was the most common Gram- Negative Bacilli in SSIs. Infection with enteric pathogens could be due to the patient’s normal flora especially when the operations are in the abdomen, P. Aeruginosa invasion of the operation sites may be a good evidence of lack of sterilization in the hospital.
The Gram-Positive Cocci, staphylococcus aureus was the predominant cause of SSIs in the current study (59%). This corresponds with Negi, V. et al 2015 (50.4%) (8) and Malik, S. et al 2011 (30.1%) (12) This predominance of S. Aureus maybe due to contamination from surgical workplace including surgical instruments and medical staff’s hands.
As for antibiotic sensitivity results, this study showed that high levels of resistance were reported for the majority of Gram- Negative Isolates. Within a range of 20-100%, the highest levels of resistance were against Ampicillin and Azatereonam and ceftazidime, whereas the most effective drugs were imipenem and meropenem followed by amikacin. P. Aeruginosa. The most common pathogen of Gram-Negative Bacilli isolate in the present study showed high resistance to ceforoxim, cefotaxim, cefoxitin and ampicillin (100%), 91% resistance to azatereonam and clotrimoxazol, 73% to gentamycin, and complete sensitivity to imipenem and meropenem, this results correspond to the results of Bajaj, A. et al 2017 (15), Vikrant, N. et al 2015 (8) and Malik, S. et al 2011 (12). As for the E. Coli isolates, the highest resistance was to ceftazidime, azatereonam and ampicillin, and the highest sensitivity was to imipenem, meropenem and amikacin, followed by cefoxitin. These results do not correlate with the results of the study that was conducted by Adwan, Gh. et al 2016 (7) which reported less resistance to ceftazidime. This potential difference between the present study results and others is perhaps due to the difference in composition of used drugs, or bacterial strains variation.
CONCLUSION:
Although Gram-Negative Bacilli were the most frequent isolates from SSIs, staphylococcus aureus was the predominant pathogen especially from surgical workplace. Therefore, all surgical departments should routinely determine the specific patterns of bacterial isolates from SSIs, check out all parts of surgical instruments and medical staff’s hands, in addition to the antibiotics sensitivity to facilitate the management of SSIs.
ACKNOWLEDGEMENTS:
I would like to thank Dr. Oussama Mansour, Faculty of Pharmacy, Al-Alandalus University, Tartous, Syria, for his scientific contribution and guidance. I would also like to thank the technical staff in the central laboratory, and the Department of Surgery at Al-Mouasat Hospital for their help during my research.
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Received on 22.01.2018 Modified on 23.02.2018
Accepted on 16.03.2018 © RJPT All right reserved
Research J. Pharm. and Tech 2018; 11(5):2070-2073.
DOI: 10.5958/0974-360X.2018.00384.0