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 Table of Contents  
Year : 2022  |  Volume : 34  |  Issue : 4  |  Page : 442-446

Antibiotic susceptibility of the bacteria causing odontogenic infections: An observational study

1 Oral Medicine and Radiology, Mahatma Gandhi University of Medical Sciences and Technologies, Jaipur, Rajasthan, India
2 Oral Medicine and Radiology, D. Y. Patil Dental College, Pune, Maharashtra, India
3 Oral Medicine and Radiology, Jodhpur Dental College, Jodhpur, Rajasthan, India

Date of Submission09-Jul-2022
Date of Decision23-Nov-2022
Date of Acceptance23-Nov-2022
Date of Web Publication09-Dec-2022

Correspondence Address:
Neeraj Kumar
Mahatma Gandhi Dental College and Hospital, RIICCO Institutional Area, Sitapura, Jaipur, Rajasthan
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jiaomr.jiaomr_194_22

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Introduction: Odontogenic infection is polymicrobial, consisting of various facultative and strict anaerobes. The dominant isolates are strictly anaerobic gram-negative rods and gram-positive cocci. Aims and Objectives: To identify the most common microorganisms responsible for causing infection and different species in oral infections. To evaluate the common types of dental infections and its site. To identify the sensitivity and resistance of antibiotics. Materials and Method: This study was conducted on 62 subjects, of which 11 showed no pathogens. After collection of the sample, it was sent to the microbiology laboratory for aerobic and anaerobic culture, gram staining, and antibiotic susceptibility test. Results: Staphylococcus (40.3%, n = 25) was the most commonly found microorganism. Maxillary anterior (32.25%, n = 20), maxillary posteriors (32.25%, n = 20), and mandibular posteriors teeth (27.4%, n = 17) showed almost similar occurrences. Maximum resistance was shown to co-trimoxazole (70.5%), amoxicillin (62.7%), erythromycin (54.9%), and azithromycin (37.25%). Linezolid (78.4%), amoxiclav and gentamicin (39.2%), vancomycin, imipenem, doxycycline showed (56.9%), and cefuroxime showed 37.25% sensitivity. Conclusions: Appropriate and correct use of antibiotics is essential to ensure that effective and safe treatment is available. The result of the present study should not be considered an absolute one; however, they can serve to increase awareness about the pathogens responsible for different infections and the sensitivity and resistance toward different antibiotics.

Keywords: Antibiotic resistance, antibiotic susceptibility, buccal space infection, odontogenic abscess, orofacial infections
Key Message: Antibiotics should be chosen wisely according to the odontogenic infection. It is important to prescribe antibiotics in the correct dose and durations to combat the problem of resistance that may develop because of their injudicious use.

How to cite this article:
Kumar N, Khare VV, Jamdade A, Aggarwal A, Rathore NS, Yadav S. Antibiotic susceptibility of the bacteria causing odontogenic infections: An observational study. J Indian Acad Oral Med Radiol 2022;34:442-6

How to cite this URL:
Kumar N, Khare VV, Jamdade A, Aggarwal A, Rathore NS, Yadav S. Antibiotic susceptibility of the bacteria causing odontogenic infections: An observational study. J Indian Acad Oral Med Radiol [serial online] 2022 [cited 2023 Feb 3];34:442-6. Available from: http://www.jiaomr.in/text.asp?2022/34/4/442/363021

   Introduction Top

Orofacial infections have plagued humankind for as long as our species has existed. Most of these infections are odontogenic and are one of the most frequently occurring infectious processes known to both antiquity and present-day health practice.[1],[2] Surgical incision and drainage may also obviate the use of an antibiotic or may increase the effectiveness of an antibiotic as the vascular flow is restored. However, antibiotics are prescribed when an acute bacterial infection has progressed, or antimicrobial therapy might benefit patients.[3],[4] Dentists benefited greatly from the discovery of penicillin because penicillin-sensitive microorganisms cause most orofacial infections.[5] The microbiological environment has been polluted with bacteria resistant to many antibiotics; this alteration in antibiotic sensitivity is now the expected result of the widespread use of antibiotics.[6],[7] The risk of the individual patient from a single antibiotic prescription is small, but altered bacterial flora represents a present and future risk to the community. This study aims to evaluate the most common microorganisms responsible for causing infection and different species in oral infections, to evaluate the common types of dental infections and its site, and to identify the sensitivity and resistance of antibiotics.

   Subjects and Methods Top

An observational study was conducted on 62 subjects in the Department of Oral Medicine and Radiology, out of which 11 subjects did not show any pathogens for 1.5 years. Patients having odontogenic infections were selected. Every precaution was taken to protect the privacy of research subjects and the confidentiality of their personal information. Written informed consent was obtained from each subject to enroll in this study. Ethical clearance was obtained from the ethical committee at the Mahatma Gandhi University of Medical Sciences and Technologies, Jaipur.

Odontogenic infections are a mixed type of infection; subjects with periapical abscesses, periodontal abscesses, and space infections were included in this study. Cases in which infection was localized and pus formation was found were only taken for the study. Patients who have taken a recent course of antibiotics within 1 month of duration, patients taking steroids (prednisolone, betamethasone, dexamethasone, and hydrocortisone), nonodontogenic origin infections, and patients with any systemic disease were excluded from the study.

All samples were collected on swab sticks as shown in [Figure 1]a, [Figure 1]b, [Figure 1]c, [Figure 1]d. All the chosen cases had draining pus/sinus or pointed abscess intraorally. It was ruptured on applying pressure or by a stab incision and transported to the Department of Microbiology for culture and antibiotic susceptibility testing. Immediately after receiving the sample, it was processed in the microbiology lab. Simultaneously, the culture was done for both aerobic and anaerobic bacteria (growth is assessed for 24–48hr). The specimen was inoculated on blood agar and MacConkey's agar for aerobic culture.[8] For the anaerobic culture, a sample in Robertson cooked meat media was inoculated into blood agar and immediately packed in an anaerobic gas pack jar. Aero tolerance test was done to determine organism was a strict (obligate) anaerobe or facultative anaerobe. Gram staining was done as usual/routine methods. The presence or absence of bacterial forms was noted. It is an essential procedure for identifying bacteria (both gram-positive and gram-negative) cell morphology and arrangement (pairs, chains, and clusters). After the bacterial cultures, the colonies were identified by gram staining and biochemical tests done for confirmation of bacteria. Antibiotic susceptibility testing: All significant isolates were inoculated on Mueller Hinton agar and Kirby-Bauer's disk diffusion was used to determine the zone diameters of these strains.[9],[10] The results were read by a microbiologist and then transferred to the Excel sheet of Microsoft Office Suite 2007 along with the details of each patient from the pro forma.
Figure 1: (a) Odontogenic infection. (b) Sample collection with bud. (c) Sample collection. (d) Sample collection

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   Results Top

Statistical analysis

This observational study contains qualitative data only, so all the data was transferred to Microsoft Excel sheet version 2007, and percentage values were derived from the data. No statistical test is applied in this study because the data is purely qualitative. Among all subjects, 32.25% (n = 20) of patients with upper anterior teeth were involved, 32.3% (n = 20) of patients with upper posterior teeth were involved, 27.4% (n = 17) of patients with lower posterior teeth were involved, and 8.04% (n = 5) of patients with lower anterior teeth were involved [Table 1].
Table 1: Teeth involved

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Among all subjects, 40.3% (n = 25) of the sample showed staphylococcus as a pathogen, 14.5% (n = 9) of the sample showed streptococcus, 9.67% (n = 6) of the sample showed Klebsiella, 8.06% (n = 5, n = 5) of the sample showed Enterococcus and E. coli, 1.6% (n = 1) of the sample showed Acinetobacter, and 17.7% (n = 11) of the sample showed no pathogen [Table 2] and [Figure 2]. Microbes are associated with the type of infections [Table 3] and [Figure 3], and as the following staphylococcus was the most common microorganism in periapical and periodontal infections. In 41.2% (n = 21) and 7.8% (n = 4) of periapical and periodontal origin, samples showed staphylococcus as a pathogen.
Table 2: Type of microorganism

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Figure 2: Type of microorganism

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Table 3: Microbes associated with type of infections

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Figure 3: Microbes associated with type of infections

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Antibiotic sensitivity and resistance were shown as follows [Table 4] and [Figure 4]a and [Figure 4]b. Maximum sensitivity was shown to linezolid (78.4%) followed by amoxclav (58.8%), vancomycin, imipenem, and doxycycline (56.9%), gentamicin (39.2%), clindamycin (37.25%), and cefuroxime (37.25%) in descending order. The least sensitivity (0%) was shown to ampicillin, cefotaxime, ceftazidime, ceftriaxone, cefepime, piperacillin, piperacillin + tazobactum, and zztreonam. 9.8% sensitivity was shown to ciprofloxacin and cefixime. Antibiotic resistance is as follows [Table 5] and [Figure 5]a and [Figure 5]b: Maximum resistance was shown to co-trimoxazole (70.5%) followed by amoxicillin (62.7%), erythromycin (54.9%), azithromycin (37.25%), and amoxiclav (33.3%) in descending order. The least resistance (0%) was shown to linezolid, vancomycin, gentamicin, ticillin + clavulanate, and colistin. 7.8% resistance was shown to levofloxacin and 9.8% to the following drugs: cefoxitin, piperacillin, meropenem, ceftazidime, cefuroxime, clindamycin, ciprofloxacin, and ampicillin.
Table 4: Antibiotic sensitivity and resistance

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Figure 4: (a) Sensitivity. (b) Sensitivity

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Table 5: Antibiotic sensitivity and resistance

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Figure 5: (a) Resistance. (b) Antibiotic resistance

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   Discussion Top

Sometimes, the antibiotic prescription is empirical and based on the patient's clinical condition. As a result, treatment is often inappropriate and leads to the development of bacterial resistance and even multiple resistance. Therefore, the present study was conducted to elicit information about the type of microorganisms causing odontogenic infections and their antimicrobial susceptibility. The present study showed 80.6% periapical infections. The study conducted by Kohli M et al.[11] (2005), Flynn Tr et al.[12] (2006), and Gill et al.[13] (1988), who also reported periapical infection as the most common odontogenic infection. The present study showed buccal space infection (60%) as the most common infection. In studies done by Shakya N et al.[14] and Loureiro FR,[15] the most commonly involved space was buccal space 18 (60%). These findings were compared with the findings of Rega AJ.[16] where they found submandibular space (30%) more common, followed by buccal space (27.5%). In our study, anterior maxillary teeth, posterior maxillary, and mandibular posterior teeth showed almost similar occurrences. While studies done previously by Munish Kohli et al.[11] and Hunt et al.[17] showed mandibular posterior teeth involvement.

In our study, staphylococcus was found to be the most common pathogen isolated. A study done by Parker MI and Khateery SM[18] (2001), Saini S et al.[19] (2003), Naseri I et al.[20] (2009), and Mahelle A et al.[21] (2014) also reported the occurrence of Staphylococcus (43.3%) as the predominant microorganism. In our study, antibiotic sensitivity test revealed that strains were most sensitive to linezolid (78.4%), amoxiclav (58.8%), vancomycin, imipenem, doxycycline (56.9%), gentamicin (39.2%); and clindamycin, cefuroxime (37.25%). It was supported by studies done by Poveda Roda R et al.[22] which showed linezolid (95%) sensitivity, and Brescó Salinas M et al.[23] showed linezolid (94.5%) and amoxclav (90.8%). The studies done by Mahelle A et al.[21] showed sensitivity to cefuroxime (95%), gentamicin (100%), and clindamycin (79%). Shakya N et al.[14] showed amoxclav (100%), levofloxacin (90.5%), amoxicillin–clavulanic acid (81%), and linezolid (100%). While in our study least sensitivity (0%) was shown to ampicillin, cefotaxime, ceftazidime, ceftriaxone, cefepime, and piperacillin, piperacillin + tazobactam aztreonam. 9.8% sensitivity was shown to ciprofloxacin and cefixime, which contradicts the study by Shakya N et al.[14]

In our study, clindamycin showed a sensitivity of 37.25%, contrasting with Mahelle A et al.[21] showing 79% sensitivity. In the present study, erythromycin, azithromycin, and amoxicillin showed a sensitivity of 19.6%, in contrast to a study done by Mahelle A et al.[21] showed 65%, 79%, and 63%, respectively. In this study, metronidazole sensitivity was not done due to the lack of metronidazole disks in the hospital laboratory. But metronidazole is only effective against obligate anaerobes because its molecule must enter the bacterial cell before it is reduced to form the active antibacterial agent. This reduction takes place effectively only under anaerobic conditions.[20] In our study, antibiotic resistance showed that the strains were resistant to co-trimoxazole (70.5%), amoxycillin (62.7%), erythromycin (54.9%), and azithromycin (37.25%). The study was done by Poveda Roda R et al.[22] showed resistance to erythromycin (39.1%) and azithromycin (33.2%). A study was done by Mahelle A et al.[21] showed azithromycin (21%) and amoxicillin (37%) resistance. While the least resistance (0%) was shown to linezolid, vancomycin, gentamicin, ticillin + clavulanate, and colistin. 7.8% resistance was shown to levofloxacin and 9.8% to the following drugs: cefoxitin, piperacillin, meropenem, ceftazidime, cefuroxime, clindamycin, ciprofloxacin, and ampicillin. It was supported by a study done by Swenson et al.[24]

   Conclusion Top

Antibiotics are invaluable adjuncts in the management of orofacial infections. Although they are not a substitute for definitive treatment, their judicious use can shorten infective periods and minimize associated risks, such as spreading infections to adjacent anatomical spaces or systemic involvement. However, increasing microbial resistance to antibiotics is a well-documented and serious global health concern.


A study should be designed using a larger sample size.


Age and sex correlation with the microorganism and antibiotic sensitivity should be evaluated. Oral hygiene and its association with the microorganism should be studied. Specific antibiotic sensitivity against specific microorganisms should be studied. Antibiotic susceptibility and microbiological analysis of nonodontogenic infections should also be studied.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

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Sandor GK, Low DE, Judd PL, Davidson RJ. Antimicrobial treatment options in the management of odontogenic infections. J Can Dent Assoc 1998;64:508-14.  Back to cited text no. 3
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]


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