|Year : 2019 | Volume
| Issue : 2 | Page : 114-117
Bacteriological profile of post-operative orthopedic implant infections and their antibiotic sensitivity pattern in a tertiary care hospital of southern Odisha
Samir K Sarangi, Sanghamitra Padhi
Department of Microbiology, M.K.C.G. Medical College, Berhampur, Odisha, India
|Date of Submission||28-Mar-2019|
|Date of Acceptance||13-Apr-2019|
|Date of Web Publication||30-Jul-2019|
Dr. Sanghamitra Padhi
Department of Microbiology, M.K.C.G. Medical College, Berhampur, Odisha
Source of Support: None, Conflict of Interest: None
Context: Prosthetic replacements and implants are becoming common in orthopedic operations for successfully alleviating the pain and improving the mobility in damaged joints. This sometimes leads to microbial infections contributing to high morbidities and prolonged hospital stay.
Aims: This study was aimed to find out (1) the prevalence of bacterial infection in orthopedic implant surgeries; (2) to isolate and identify the bacteriological agents responsible for causing post-operative orthopedic implant infections; and (3) to perform their antimicrobial sensitivity.
Methods: This was a prospective study carried out at a tertiary care hospital of southern Odisha, over a period of 24 months. The study was conducted on 112 cases of infected implants from orthopedic wards, from 1st January 2016 to 31st December 2018. Pus samples were collected using three sterile swabs. One was used for Grams stain, one for inoculation on MacConkey and Blood agar, and the 3rd one for inoculation in Robertson's cooked meat (RCM) broth. Blood agar and MacConkey agar plates were processed for culture of aerobic bacteria, while the RCM inoculate was processed for anaerobic bacteria. Biofilm production and Susceptibility testing was performed.
Results: Out of the 112 samples processed, culture positivity was observed in 90 specimens. Among them, 78 were aerobic, while 12 were anaerobic infections. Staphylococcus aureus (35.89%) was the predominant aerobic isolate followed by Pseudomonas spp. (28.2%). Among anaerobes, Bacteroides spp. (7.7%) was the most common isolate.
Conclusion: The appropriate pre- and post-operative care should be taken to prevent such infections. Staphylococcus spp. was the commonest isolate and its ability to produce biofilm stresses the need for an appropriate antibiotic policy to put in place to eradicate the infection.
Keywords: Antibiotic sensitivity, biofilm, infection, orthopedic implants
|How to cite this article:|
Sarangi SK, Padhi S. Bacteriological profile of post-operative orthopedic implant infections and their antibiotic sensitivity pattern in a tertiary care hospital of southern Odisha. J NTR Univ Health Sci 2019;8:114-7
|How to cite this URL:|
Sarangi SK, Padhi S. Bacteriological profile of post-operative orthopedic implant infections and their antibiotic sensitivity pattern in a tertiary care hospital of southern Odisha. J NTR Univ Health Sci [serial online] 2019 [cited 2020 Apr 2];8:114-7. Available from: http://www.jdrntruhs.org/text.asp?2019/8/2/114/263639
| Introduction|| |
Prosthetic replacement and implant surgery is one of the most commonly performed orthopedic operations for successfully alleviating the pain and improving the mobility in damaged joints. But infection remains a major obstacle leading to implant failure, contributing to increased morbidity and mortality. Infection can occur by infected implant, aseptic failure, predisposing patient conditions, biofilm production on implant by bacteria. Although less common, nowadays still infection is a major threat for treatment outcome as it can lead to malunion or nonunion of fracture, prosthetic joint replacement failure with increased morbidity. Microorganisms can adhere and grow on implant by biofilm production which is also the cause of major antibiotic resistance among biofilm producing bacteria.
Nowadays, most of the bacterial isolates are showing resistance to the major first line drugs. Moreover, each hospital has different microbial flora and also show different antibiotic susceptibility pattern so that empirical antibiotic therapy can be started based on those pattern. Hence, this study was conducted to find out the prevalence of bacterial infection in orthopedic implant surgeries, to isolate and identify the bacteriological agents responsible for causing post-operative orthopedic implant infections and to perform the antimicrobial sensitivity of the bacterial isolates.
Subjects and Methods
This was a prospective study carried out in the department of Microbiology of a tertiary care hospital in southern Odisha over a period of 24 months. The study was conducted on 112 cases of infected implants from orthopedic wards of the tertiary care hospital and some private clinics, from 1st January 2016 to 31st December 2018.
The samples for the bacteriological examination were obtained from the discharges which were adjacent to the infected implant and tissue, using three sterile cotton swabs or a sterile disposable syringe. First swab was used for gram staining and ZN staining, second was for aerobic culture in blood and MacConkey agar, and the third was for anaerobic culture in Robertson's cooked meat broth.
The isolates were identified by using standard microbiological procedures and were tested for their antimicrobial susceptibilities by the Kirby Bauer's disc diffusion method according to the guidelines of the CLSI. Biofilm detection was done by Tube method, Congo red agar method and Tissue culture plate method.
| Results|| |
Among total of 112 patients investigated, culture positivity was found in 90 cases (80.4%) and 22 (19.6%) were found culture negative.
Biofilm production was detected by 3 methods like tube method, tissue culture method and Congo red agar method among aerobic bacteria. Highest sensitivity was shown by tissue culture method. Drug resistance was higher among biofilm producers in comparison to non-biofilm producers, conferring that biofilm production is a major factor for emergence of resistance.
| Discussion|| |
Implant-related infections continue to pose a problem for the orthopaedicians. In our study, majority (32.1%) of cases were noticed in 21-30 year age group with a male preponderance (53.6%) [Table 1]. This is similar to the data shown by Benazin S et al., where most of the patients belonged to 20-39 year age group with a male preponderance. These young males belong to actively working age group of the community and are more vulnerable to road traffic accidents, sports injuries and other industrial accidents. Most commonly affected site involved with infection was femur (33.9%) [Table 2], which is consistent with the study of Singh R et al. In road traffic accidents, lower extremity fractures occur due to the interaction of gravitational force and the impact absorption by the lower limbs at the time of accident. Most of the cases (26.7%) were open fractures and associated with tissue damage [Table 3]. These fractures were mainly open with extensive soft tissue damage, hematoma formation and wound contamination which might have led to the spread of bacteria to the bone leading to grievous infection. Old age was responsible for 17.8% cases in contrast to 8.09% cases in the study of Fernandes A et al. The elderly patients often having several risk factors like hypertension, cardiac abnormalities, malignancies and diabetes mellitus might be the risk factors.
Out of 112 cases, aerobic bacterial isolates was noticed in 78 cases. Staphylococcus aureus was found to be the most common aerobic isolate (31.1%) followed by Pseudomonas aeruginosa [Table 4]. Similar study showing Staphylococcus aureus as the most common isolate was cited by Roopa Shree et al. and Jyoti et al., A study done by Khosravi et al. also reported Staphylococcus aureus as most common isolate followed by Klebsiella ozaene and Pseudomonas aeruginosa.
In our study, Bacteroides fragilis (7 out of 12) was the most common anaerobic isolate followed by Peptostreptococcus [Table 4]. Majority of Gram positive bacteria showed resistance to cefpodoxime (70%) and cefepime (44.4%) [Figure 1] while majority of Gram negative isolates were resistant to cefotaxime (63.6%) and levofloxacin (52%) [Figure 2].
Biofilm are microbial communities encased within a polysaccharide rich extracellular matrix on the surface of implants. They are associated with an increased resistance to antimicrobial agents leading to treatment failures. To find out the association between drug resistance and biofilm production, we used tube method, tissue culture plate method and Congo red agar method for detection of biofilm production, among which tissue culture plate method was found to be most sensitive, showing 82% of positivity [Table 5]. Biofilm production was noticed among 83.3% levofloxacin resistant, 72.7% cefpodoxime resistant, 71.4% cefepime resistant, 66.7% of amoxycillin-clavulanic acid resistant and 66.7% of ampicillin-sulbactam resistant bacteria [Table 6]. Biofilm makes the microcolonies impermeable to antibiotics, hydroxyl radicals and superoxide anions which bind to the outer surface of the matrix layer of biofilm.
|Table 6: Comparison Of Resistance Between Biofilm Producing And Non-Producing Bacteria|
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]