ETIOLOGICAL BACTERIAL SPECTRUM OF PATIENTS WITH ODONTOGENIC AND NON-ODON-TOGENIC ABSCESSES AND PHLEGMONS IN THE MAXILLOFACIAL AREA

Background: Clarifying the bacterial causes of inflammatory diseases has a major role in the treatment of this type of pathology. Materials and methods: In a retrospective study of 138 adult patients with abscesses and phlegmons of the head and neck, hospitalized and operated on urgently in the Clinic for Maxillofacial Surgery at University Multispecialty Hospital for Active Treatment “Sveta Marina” EAD – city of Varna, Bulgaria. Depending on their origin, the patients were divided into two groups - with odontogenic and non-odontogenic abscesses. Results: The study group consists of 73 men (52.9%) and 65 women (47.1%) with a mean age of 43 (18-84) years. The mixed resident microflora, including more than one bacterial species, is isolated in the largest number of cultures – 64.2%. The total number of cultures with Gram-positive bacteria isolated in the samples of the studied 92 patients with isolates is 20,33%. Representatives


INTRODUCTION
Abscesses in the maxillofacial area in relation to the severity of the flow and the area affected by the purulent exudate can vary in very wide limits -from small abscesses with weak symptoms, which can be treated on an outpatient basis, to large-spread purulent foci of the spilled area (phlegmons), which together with their complications can lead to a long stay in intensive care units and end in death [1]. The latter must be treated in specialized surgical clinics and the operation is performed under general anesthesia. Antibacterial treatment for acute inflammatory diseases of the head and neck, such as abscesses and phlegmons, necessarily requires the use of antibacterial therapy [2]. Clarifying the bacterial causes of inflammatory diseases has a major role in the treatment of this type of pathology. It is key in determining the type of antibiotic that is administered to patients with abscesses and phlegmons in the maxillofacial area when it is taken into consideration the resistance of the isolated microbe. In our clinical practice, we appoint and start the application of the appropriate antimicrobial drug empirically -before the isolation of the causative bacterial agent, already at the time of the diagnosis, the culture of which is usually presented a few days after taking the pus for examination [3,4]. In some cases, no microbial pathogen is isolated (no culture), and some authors even speak of culture-negative abscesses [4,5]. In these cases, relatively new methods are increasingly applied to determine the type of pathogens by isolating and studying their genome [6,7]. Such methods are the detection of 16S rRNA and DNA sequences of the pathogens [4,8,9]. However, they are unable to detect fungal microorganisms [10].

MATERIALS AND METHODS
In a retrospective study of 138 adult patients with abscesses and phlegmons of the head and neck, hospitalized and operated on urgently in the Clinic for Maxillofacial Surgery at University Multispecialty Hospital for Active Treatment "Sveta Marina" EAD -city of Varna, Bulgaria in the period from 01.07.2021 to 31.06.2022 were https://doi.org/10.5272/jimab.2023292.4958 included. In all of them, the diagnosis was confirmed during the operative intervention by the evacuation of the purulent exudate. In all patients, material was taken for microbiological examination and preparation of an antibiogram as a routine examination. Depending on their origin, the patients were divided into two groups -with odontogenic and non-odontogenic abscesses.

RESULTS AND DISCUSSION
The study group consists of 73 men (52,9%) and 65 women (47,1%) with a mean age of 43 (18-84) years -42 (18-84) for men and 45 (18-84) for women. Figure 1 shows the distribution of patients in the study group by number and gender.  Tables 1 and 2 show the distribution of the studied patients from the study group by gender, age groups and mean age. As can be seen from the results presented in Tables 1 and 2, the proportion of patients is younger. With increasing age, the number of patients with abscesses and phlegmons in the maxillofacial area decreases. The largest share of patients is at a young age (up to 44 years), and the smallest is among old people (between the ages of 75 and 89). There is no data in the world literature explaining this phenomenon. The most likely reason for this is the reduction of teeth in the dentition as the human race ages. The gender distribution did not show significant differences, both in the odontogenic and non-odontogenic abscess groups, and requires special comment.
In 46 of all 138 patients (33.33%), no specific pathogen was isolated, these are the so-called culture-negative abscesses. The most likely reason for this is that the anaerobic causative agents of infectious diseases, due to the non-observance of the conditions in the storage and transportation of the samples, die [4]. Separately, they are difficult to cultivate [11]. The remaining 92 patients (50 with odontogenic and 42 with non-odontogenic abscesses and phlegmons) were divided into groups according to the microorganisms isolated and the results obtained are presented in Table 3 and Graphic 1.  The mixed resident microflora, including more than one bacterial species, is isolated in the largest number of cultures -60, which represents 64,2%.
The total number of cultures with Gram-positive bacteria isolated in the samples of the studied 92 patients with isolate is 19, i.e. 20,33%. They are coagulase-negative staphylococci (Staphylococcus coagulase negative, CNS), S. aureus, S. anginosus and S. viridans.
The classic causative agent of purulent infections, S. aureus, is isolated in 5 of all 92 samples, which is 5,35%.
Representatives of Gram-negative bacteria are isolated in 7 of all 92 cultures of the examined patients, which is 7,49%. These are E. coli, E. cloacae, P. aeruginosa and S. maltophilia. E. coli is found in 3 of the samples taken and constituted 3,21% of the total. E. cloacae is isolated in 2 of all wound secretions and represented 2,14%.
S. maltophilia is also observed in only 1 of all cultures (1,07).
It can be concluded that Gram-positive bacteria are more than 2,7 times more than Gram-negative (19 versus 7), fungi are 4, and obligate anaerobes are only 2.
The largest number is of the resident microflora as the cause of the evacuated exudate -a total of 70 out of 92 (74,9%), of which 60 are mixed microflora that contains more than one type of bacteria, and 10 (Staphylococcus coagulase negative) are only with one isolated bacterial agent each.
Eight of all 138 patients have diffuse purulent inflammation (phlegmon) of the soft tissues in the maxillofacial region -6 with phlegmon on the floor of the oral cavity of odontogenic origin and 2 with facial phlegmon of non-odontogenic origin. In four of these patients with phlegmon on the floor of the oral cavity of odontogenic origin, a monoinfection with the following causative agents is found -S. epidermidis, S. haemolyticus, S. anginosus and S. maltophilia. In one of them, resident microflora is demonstrated, and in one, the cultures remained sterile (wound discharge without microbial growth). The pathogens found in the patients with facial phlegmon of non-odontogenic origin are E. coli in one patient and E. cloacae in the other. I.e. in patients with phlegmon of odontogenic origin, the ratio of Gram-positive to Gram-negative bacteria is 3:1, and in phlegmonous inflammations of non-odontogenic origin, the causative agents are from the Gram-negative spectrum. Taken together for the entire group of patients with phlegmons in the maxillofacial area, the ratio of Gram-positive to Gramnegative bacteria to resident microflora to sterile cultures is 3:3:1:1.
Graphic 2 presents the distribution of patients with phlegmonous inflammations in the maxillofacial area in relation to their etiological cause.

Graphic 2.
Etiological spectrum of the studied patients from the studied group with phlegmons CONCLUSIONS Microorganisms are not isolated in a third of the examined patients, which are most likely long errors in taking material for microbiological examination or in its improper storage and transportation. Of the other crops, the share of resident microorganisms as opportunistic pathogens is the largest. Of the conditionally pathogenic microorganisms, Gram-positive ones predominate. Gramnegative bacteria were the only causative agents of phlegmons of non-odontogenic origin.