Abstract

Introduction

The parotid gland may be injured either bluntly or by penetration in head and neck trauma. Traumatic parotid pathologies account for 2.5% of all parotid pathologies [1,2]. In injuries occurring at the gland level, the parenchyma is affected, whereas injuries involving the anterior aspect of the gland may involve the Stensen’s duct. The risk of facial nerve involvement in parotid gland injuries makes these pathologies particularly significant [1].

Parotid abscess (PA) typically develops following acute purulent sialadenitis. Reported risk factors for PA include poor oral hygiene, immunosuppression, sialolithiasis, and dehydration. Due to its anatomical relationship with the facial nerve, PA presents a therapeutic challenge [3]. The primary treatment strategy consists of drainage and appropriate antibiotic therapy [3-5]. While the most frequently reported pathogens in PA are Staphylococcus spp., anaerobic bacteria, and Streptococcus spp., numerous other pathogens have also been isolated in PA cases [3,4]. The differential diagnosis of PA also includes sialadenitis, sialolithiasis, soft tissue infections of dental origin, and temporomandibular joint disorders [3-6].

Kocuria kristinae is an aerobic, gram-positive, catalase-positive, coagulase-negative, and non-hemolytic coccus that is part of the skin and oral flora [7-11]. Kocuria kristinae is generally considered to become pathogenic in immunosuppressed patients [7-9,11]. The most common infections associated with Kocuria spp. include bacteremia, skin and soft tissue infections, endophthalmitis, infectious endocarditis, and peritonitis. Recently, an increasing number of Kocuria spp. infections were reported in immunocompetent individuals [11].

In this case report, a patient with parotid abscess secondary to blunt trauma, in which Kocuria kristinae was identified as the causative pathogen, is presented in light of the literature. This is the first reported case in the literature both in terms of its development secondary to blunt trauma and the isolation of Kocuria kristinae in culture.

Case Report

A 30-year-old male patient with no known medical history was referred from the Emergency Department to the Otorhinolaryngology clinic due to painful swelling over the mandible. It was learned that five days prior, he had sustained a blunt trauma to the affected area while playing football. The patient reported experiencing pain immediately after the impact, with no mandibular fracture detected upon evaluation in the Emergency Department, and no open wound associated with the trauma. Over the past two days, he had developed swelling in the painful area, with increasing pain intensity. On physical examination, a lesion was observed at the level of the left mandibular angle, characterized by erythema and increased temperature of the overlying skin, as well as tenderness and fluctuance upon palpation (Figure 1).

Figure 1 Lesion at the left mandibular angle, causing erythema and increased temperature of the skin, tender, and exhibiting fluctuation.

Trismus was present, with restricted and painful mouth opening of approximately 2 cm. Serous saliva of normal consistency was observed flowing from the Stensen’s duct orifice. No additional significant findings were noted on physical examination. Neck ultrasonography revealed a dense fluid collection of approximately 3×2 cm within the left parotid gland, suggestive of an abscess. To further evaluate potential post-traumatic fractures, the extent of abscess spread, its origin, and involvement of cervical spaces, contrast-enhanced neck computed tomography (CT) was performed. A well-defined collection measuring approximately 3 cm in diameter, consistent with an isolated abscess within the left parotid gland, was observed (Figure 2).

Figure 2A Contrast-enhanced CT showing an abscess-like image within the left parotid parenchyma, white arrow, axial section.

Figure 2B Contrast-enhanced CT showing an abscess-like image within the left parotid parenchyma, white arrow, coronal section.

No additional findings were detected on radiological examination. The patient’s blood test results are presented in Table 1.

Table 1 C-Reactive Protein and Complete Blood Count Results During Follow-Up

For possible dental etiology, the Endodontics Clinic was consulted for the patient. He reported no dental symptoms before or after the trauma. Based on history and dental examination, a dental pathology was not considered as the cause of the abscess. Abscess drainage was performed, yielding a thick, purulent fluid. Following drainage, trismus improved. The abscess sample was collected and sent to the microbiology laboratory. After drainage, based on the recommendation of the Infectious Diseases specialist, intravenous ampicillin-sulbactam (4×1.5 g) was initiated. On the third day of treatment, significant clinical and laboratory response was observed, and based on the recommendation of the Infectious Diseases specialist, the patient was discharged with oral amoxicillin-clavulanate (2×1 g). Cultures from the parotid abscess were cultivated using sheep blood agar and eosin methylene blue agar plates. The plates were incubated at 37 °C for 48 hours. Tiny, smooth, shiny, and non-hemolytic colonies were observed on blood agar, whereas no growth was detected on eosin methylene blue agar. Gram staining of the colonies revealed gram-positive cocci. The organism was catalase-positive and coagulase-negative. Identification was performed using the Vitek 2 system (BioMérieux, France), and the isolate was identified as Kocuria kristinae. Antibiotic susceptibility testing was not performed due to the absence of defined breakpoints for Kocuria kristinae in the EUCAST guidelines [12]. At the follow-up examination on post-drainage day 10, the patient showed no signs of infection on physical examination, and C-reactive protein levels had returned to normal; therefore, antibiotic therapy was discontinued.

Informed consent was obtained from the patient for the publication of this case report.

Discussion

Although PA is considered to be more common in elderly and/or immunosuppressed patients, multiple studies demonstrated its occurrence in healthy individuals across all age groups [3-5]. On physical examination, a fluctuating swelling in the parotid region is the most critical finding suggestive of an abscess. CT or ultrasonography provides sufficient information for the diagnosis of an abscess. When complications are suspected, CT is the preferred imaging modality [4]. Reported complications include facial nerve paralysis, cervicofacial cellulitis, osteomyelitis, temporal lobe abscess, deep neck infections, necrotizing fasciitis, mediastinitis, airway obstruction, and septic shock. Prompt diagnosis and effective treatment are crucial to prevent these complications [3,4]. Abscess drainage can be performed via aspiration or incision [4]. Aspiration drainage is recommended as the initial approach due to its lower risk of facial nerve injury [5]. The recommended duration of antibiotic therapy is generally 10–14 days [3,4]. To date, there are no reported cases of PA secondary to blunt trauma in the literature. Possible etiological mechanisms in our case include the parenchyma becoming susceptible to infection due to the effects of extravasated saliva following trauma or secondary infection of an associated hematoma.

Previously, Kocuria spp. was classified as Micrococcus or coagulase-negative Staphylococcus when bacterial typing was performed manually. However, more accurate identification has been achieved with the advances in automated systems [7]. The most commonly used method for identification is VITEK 2 [9,11]. Since this bacterium is generally regarded as a contaminant, its pathogenic potential has often been overlooked. However, in recent years, an increase in both superficial and deep tissue infections caused by Kocuria spp. was reported [7]. Due to phenotypic similarities between Kocuria spp. and coagulase-negative Staphylococcus spp., misidentifications between these genera have occurred. Currently, there are no established treatment guidelines for Kocuria infections, and empirical treatment is initiated in most cases. It was reported that Kocuria spp. is generally susceptible to amoxicillin-clavulanate [11].

In a study by Chaubey et al., infections caused by Kocuria kristinae were evaluated in patients undergoing treatment for head and neck malignancies. In this case series, male patients were predominant, which was attributed to the higher incidence of head and neck cancers in men. Similarly, the mean age was reported as 50.8 years, but this finding was not considered significant on its own. It was demonstrated that Kocuria kristinae infections occur in a wide age range, from neonates to elderly individuals. In the study by Chaubey et al., most patients exhibited leukocytosis and elevated CRP levels [7]. Amina et al. reported a case of meningitis secondary to sphenoid sinusitis in a pediatric patient without immunosuppression, in which Kocuria kristinae was identified as the causative agent. The pathogen was found to be susceptible to penicillin G, amoxicillin, cefotaxime, erythromycin, spiramycin, lincomycin, ofloxacin, pristinamycin, levofloxacin, teicoplanin, and vancomycin, while exhibiting low-level resistance to streptomycin, kanamycin, and gentamicin. The patient was successfully treated with a combination of cefotaxime and vancomycin [8]. Tsai et al. reported a case of a brain abscess caused by Kocuria spp. in a 52-year-old patient with diabetes mellitus. In this case, the pathogen was found to be susceptible to penicillin, cloxacillin, cefmetazole, clindamycin, meropenem, penicillin G, ampicillin/sulbactam, and piperacillin/tazobactam [9].

Conclusion

Early and effective treatment of PA is crucial for preventing complications. Accurate identification of the causative bacterium is essential for appropriate antibiotic therapy planning. With the introduction of advanced technological systems, bacterial classification has become more precise. This has led to the recognition of certain previously overlooked bacteria as causative agents in various infections. A similar situation applies to Kocuria kristinae.

Acknowledgement

None. 

Informed Consent

References

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