Background and aims: A fracture of the mandible is referred to as a mandibular fracture or jaw fracture. The fracture occurs in two locations in approximately 60% of cases. This may result in decreased ability to open the mouth. The teeth often feel misaligned, and the gums may bleed. This study aimed to determine the etiology of fractures, surgical management, bacterial causes of postoperative infection, and the antibiotic profile of bacteria isolated from maxillofacial fracture patients at the Military Hospital in Sana'a.

Materials & methods: Between January 1, 2024, and the end of December 2024, this study included patients with maxillofacial fractures at the Military Hospital in Sana'a, Yemen, where the Department of Oral and Maxillofacial Surgery conducted the study. Thirty patients received treatment with fracture fixation devices. Patients underwent treatment and follow-up six months after surgery. The incidence of postoperative bacterial infections at surgical sites after removal of the devices was assessed. Isolates were identified using standard microbiological methods, and antibiotic susceptibility testing was performed using the Kirby-Bauer technique. Clinical and demographic data of the study participants were also collected.

Results: The study reveals that the majority of patients with maxillofacial fractures in Sana'a, Yemen, were aged 20–24 years, with a mean ± standard deviation of 29.9 ± 12.4 years. All were male, with gunshot wounds and road transport accidents being the most common causes. Most fractures were open compound fractures (56.7%), all of which were mandibular fractures. Open reduction internal fixation (ORIF) was the most common surgical treatment performed in 60% of patients. The most common bacteria isolated from surgical sites was Staphylococcus aureus, accounting for 27 (90%) of all isolates, followed by Klebsiella pneumoniae at 30%, while three cases (10%) showed no bacterial growth. Amoxicillin, Augmentin, Aztreonam, Cefotaxime, Cefoxitin, Ceftazidime, Piperacillin, Ceftriaxone, and Doxycycline were completely ineffective against S. aureus isolates. Vancomycin had the highest sensitivity rate against S. aureus, at 100%. Amoxicillin, Augmentin, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, cotrimoxazole, and gentamicin had no effect on Klebsiella pneumoniae isolates, while the sensitivity rate for amikacin was 33.3% and for ciprofloxacin 33.3%.

Conclusion: The study found that males were 100% more likely to suffer mandibular fractures, with the majority of cases occurring in those aged 20 to 24 (56.7%). Gunshot wounds were the most common cause. The most commonly isolated bacteria was Staphylococcus aureus, with a very high rate of multidrug resistance. Vancomycin was found to be the most reliable drug for treating Staphylococcus aureus infections.

Maxillofacial injuries are among the most common life-threatening emergencies in both developing and developed countries, accounting for between 7.4% and 8.7% of emergency medical care [1]. These injuries affect both the skeletal structures and soft tissues of the facial region and can cause significant and long-term functional, aesthetic, and psychological complications [2]. Due to the prominent location of the maxillofacial region, it is the most susceptible to fractures. The mode of injury and the direction of trauma determine the pattern and location of these fractures [3]. Fractures of the maxillofacial skeleton alone are rarely fatal, but concomitant injuries to other organs can be a complicating factor. Other severe ailments as neurological, orthopedic, and ophthalmological damage frequently accompany maxillofacial fractures [4]. Due to their near proximity to critical organs including the brain and cervical vertebrae, these injuries are frequently linked to significant morbidity; nevertheless, they can also result in loss of function, impairment, and even death [5]. In terms of severity and causation, the epidemiology and etiologies of face fractures differ amongst populations [6]. RTA and assault have been identified as the primary causes of craniofacial fractures in adults, whereas falls were the most often reported cause in younger people [7]. Comprehending maxillofacial trauma facilitates the evaluation of individuals' behavior patterns across nations and aids in the development of efficient strategies for managing and preventing injuries [8]. Surgical wound infections can be external (skin), deep (muscle and tissue), or extend to the organ or location of the surgery [9]. Surgical wound infections are frequently detected and can arise in the first 30 days following surgery, regardless of whether the bacteria were previously on the patient's skin – mucus membrane of the mouth or if they were transferred to the patient from the hospital environment or from contact with infected individuals. According to recent studies, postoperative infections can happen years after surgery, and these infection rates go unreported for a variety of reasons, including missing patient follow-up, having trouble accessing a prior surgical history, seeing a different surgeon, not meeting national records requirements, and more [10,11,12]. The CDC has divided SSIs into three categories: infections affecting organs or bodily spaces, deep wound infections, and superficial infections. The likelihood of an SSI is influenced by the level of contamination present at the surgical site at the time of the procedure. Wounds are categorized as clean, contaminated, unclean, or infected based on the degree of contamination and its incidence [13]. Because of the diverse character of this surgical infection, SSI epidemiology research provide difficulties. There are significant differences in prevalence among procedures, facilities, patients, and surgeons [14]. Both internal and foreign microbes have the ability to alter the SSI. The majority of surgical site infections are brought on by endogenous germs that are present on the patient's skin at the time of the surgical incision. The most frequent bacteria that cause skin infections are gram-positive ones, such as Staphylococcus aureus. Microorganisms within the patient's body that are exposed during surgery are more likely to be the source of SSIs. Pathogens vary according to the surgical location; for example, gastrointestinal tract surgery increases the risk of SSI from Gram-negative intestinal germs [15]. Given the risk factors for SSI, the study literature acknowledges a number of linked variables; yet, investigations are not replicable. Despite this, a number of publications have often identified significant blood loss, male sex, and advanced age as risk factors for SSI [16–19]. Additional risk factors for SSI are often categorized as postoperative, procedure-related (peri-operative), and patient-related (preoperative). In general, patient-related risk factors for surgical site infection (SSI) can be classified as either modifiable or non-modifiable. Patient-related variable risk factors include poor diabetes control, use of immunosuppressive medications, obesity, tobacco use, and length of preoperative hospitalization. Procedure-related risk factors include wound type, surgical site haircut, hypoxia, length of surgery, and hypothermia. Non-modifiable or modifiable risk factors, such as age and gender, have been considered [20]. Although previous research has been conducted on bacterial profiles, antibiotic sensitivity, and risk factors for UTI in postoperative patients at specialized hospitals in Sana'a, Yemen [21], as well as one study on general SSI, there is no information regarding SSI in maxillofacial surgery in Yemen. Therefore, this study aimed to determine the prevalence and distribution of bacterial pathogens isolated of SSI associated with postoperative wounds of maxillofacial surgery and their antimicrobial susceptibility profiles in selected hospitals in Sana'a City, Yemen.

A serial, comparative clinical follow-up study was conducted. This study comprised patients who presented with trauma at the military hospital's maxillofacial surgery department between January 1, 2023, and December 31, 2023. Age, sex, socioeconomic position, primary complaint, history of current sickness, history of previous medical conditions, length of injury, etiology, and related injuries were all detailed. Following data collection, each patient in this research underwent a comprehensive clinical examination and radiological interpretation in order to make a diagnosis.

Physical examination of patients was performed by an experienced MSc student to check for the presence of local infection based on one or more of the following criteria: pain, tenderness, local swelling, redness, warmth or purulent discharge, evidence of abscess, or fever greater than 38°C in deep incisions. Specimen Collection: Wound swabs or aspirates were aseptically collected from surgical sites of patients presenting for medical examination and removal of fixed orthopedic appliances. This was done prior to wound treatment with antiseptic solution. Specimens were then placed in 5 ml Stewart transport media and transported to the Bacteriology Department at the National Center for Public Health Laboratories for bacteriological testing.

Bacterial Isolation and Identification 

The samples underwent test methods in accordance with accepted bacteriological practices for aspirates and swabs [22].  Using the conventional streak plate method, the samples were inoculated into blood agar, Mannitol salt agar, and MacConkey agar (Oxoid). For 24 to 48 hours, the plates were incubated at 37°C in an anaerobic environment.  Colony morphology, pigment generation, blood hemolysis (beta, alpha, and gamma hemolysis), biochemical tests (lactose, mannitol, glucose, and sucrose fermentation), and motility property testing were used to validate bacterial growth on medium. Because mannitol salt agar is a selective medium for Staphylococcus, bacteria growing on both blood agar and mannitol salt agar are thought to be Gram-positive bacteria. To differentiate streptococcus from staphylococci, a catalase test was next conducted; streptococcal species were ruled out if the test yielded negative findings. Additionally, to differentiate S. aureus from other Staphylococcus species that test negative for coagulase, a coagulase enzyme test was performed. Because MacConkey agar is a selective medium for Gram-negative bacteria, microorganisms produced on it and blood agar are thought to be Gram-negative bacteria. The lactose fermentation characteristics of the colonies on MacConkey agar were used to characterize them. The colorless colonies were lactose-non-fermenters, whereas the pink-colored colonies were lactose fermenters. Using a variety of biochemical assays, such as indole, urea, Triple Sugar Iron agar (TSI), Simmon's Citrate agar, and Lysine Decarboxylase (LDC), gram-negative bacteria were further examined for motility and characterization.  To confirm that P. aeruginosa is an oxidase-positive bacterium, oxidase was used to evaluate colonies that generated color on blood agar and non-lactose fermenter on MacConkey agar.  Using a variety of biochemical tests, such as triglyceride iron agar (TSI), indole, urea, Simmon's Citrate agar, and Lysine Decarboxylase (LDC), gram-negative bacteria were also examined for their motility and ability to distinguish.  Oxidase was used to confirm P. aeruginosa (oxidase-positive bacterium) in colonies that produced color on blood agar and non-lactose fermented on MacConkey agar. Testing for Antimicrobial Susceptibility Mueller-Hilton agar (Oxoid) was used in the Kirby-Bauer diffusion technique to examine the isolates' patterns of antibiotic susceptibility. Five milliliters of nutrient broth were used to suspend four to five bacterial colonies with the same shape. After that, the suspension's turbidity was brought down to 0.5 McFarland, which produced a colony count of around 107 or 108 colony-forming units per milliliter. After inserting a sterile swab into the solution and pushing it against the tube's walls to remove any excess, the swab was infected directly in the middle of the Mueller-Hilton agar plate and then equally distributed to produce confluent growth. MuellerHilton agar was aseptically supplemented with 5?fibrinated sterile blood to test for streptococci susceptibility [22]. The relevant anti-microbial susceptibility discs were aseptically positioned and gently pushed against the medium for complete surface contact using sterile forceps after the infected plates had dried for three to five minutes. Approximately 24 mm separated the discs, and 15 mm separated them from the plate's border, to prevent the region of inhibition from overlapping. For 18 to 24 hours, the plates were incubated aerobically at 37 °C in the incubator [23]. Using a digital caliper, the diameter of the zone of inhibition for each antibiotic was measured to the closest millimeter (Market lab, UK). The diameter of the inhibition zone of tested bacteria around the disc was measured to the nearest millimeter, and then classified as sensitive and resistant according to Cheesbrough [22]  and the Clinical Laboratory Standard Institute guidelines of 2015 [23] . The antimicrobial susceptibility discs (Oxoid, Ltd, UK) includes; Amikacin (30 μg), Clarithromycin (30 μg), Amoxicillin-clavulanic acid (30 μg), Ampicillin (10 μg) Penicillin (30 μg), Erythromycin (15 μg), Ceftriaxone (30 μg), Cefixime (30 μg), Ceftazidime (30 μg), Cefotaxime (30 μg), Cefepime (30 μg), Gentamicin (10 μg), Ciprofloxacin (5 μg), Norfloxacin (10 μg), and Cotrimoxazole (25 μg) Imipenem (30 μg), Aztreonam (30 μg), Rifampicin (30 μg), and Vancomycin (30 μg).

The data were analyzed with Epi Info version 6 (CDC, Atlanta, USA). The continuous variable (age) was summarized with mean and standard deviation while the categorical variables were summarized with frequencies and proportions and presented as tables. 

Ethical Consideration: 

The Medical Ethics and Research Committee of Sana'a University's Faculty of Dentistry granted ethical permission for this project (No. 12 dated December 1, 2023). Every process complied with the review committee's ethical standards. Consent was also obtained from each participant, who was told that participation was entirely optional and that they might decline at any time for any reason.

Table (1) shows the age distribution of maxillofacial fracture patients treated with devices in the 48 hospital. The mean ± standard deviation of the patients was 29.9 ± 12.4 years, and their ages ranged from 20 to 57 years. Table  2 shows the sex distribution of maxillofacial fracture patients treated with devices in the military hospital. All patients were males and no single case of females. Table 3 shows the causes and incidence of facial and maxillofacial fractures in patients treated with devices at the 48 hospital. The most common cause was gunshot wounds, accounting for 50% of all cases, followed by traffic accidents (20%), bomb explosions (16.7%), and pathological fractures (13.3%). No cases of falls from height were recorded. The kinds of fractures among head injuries in patients receiving device treatment at the 48 hospital are displayed in Table 4. There were 43.3% of closed simple fractures and 56.7% of open complicated fractures. Table 5 lists the locations of head injuries among patients receiving device treatment in 48 institutions; all of the fractures were mandibular. Table 6 shows the types of procedures used for device removal in patients treated with devices at the military hospital . The most common procedures were reconstructive plate counting (60%), followed by miniplate counting (30%), while titanium mesh was used in only three cases (10%). Table 7 shows the clinical examination of fracture patients treated with devices at 48 hospitals. Pain at the fracture site was observed in 33.3%, fever in 36.7%, chills in 3.3%, night sweats in 43.3%, skin erythema in 46.7%, purulent discharge in 70%, pain at the fracture site in 20%, and movement at the fracture site in 10% of all cases. Table 8 shows the surgical treatments for fracture patients treated with instrumentation at Hospital 48. Open reduction internal fixation (ORIF) alone was the most common surgical treatment performed in 60% of patients, followed by open reduction internal fixation with intermaxillary fixation (IMF) at 40%, while no case was performed using open reduction internal fixation with bone grafting (0%). Table 9 shows postoperative bacterial infections from the surgical site in instrumented fracture patients at Hospital 48. The most common bacteria isolated from the surgical site was Staphylococcus aureus, accounting for 27 (90%) of the total isolates, followed by Klebsiella pneumoniae at 30%, while 3 cases (10%) showed no bacterial growth. The antimicrobial susceptibility pattern of the isolated Staphylococcus aureus (n=27) is displayed in Table 10.  Amoxicillin, Augmentin, Aztreonam, Cefotaxime, Cefoxitin, Ceftazidime, Piperacillin, Ceftriaxone, and Doxycycline were all completely ineffective against the Staphylococcus aureus isolates. Vancomycin had the highest sensitivity rate of any antibiotic against S. aureus, at 100%. Teicoplanin had the next highest sensitivity rate, at 88.9%, followed by Tobramycin at 55.5%, Gentamicin at 66.7%, and Co-trimoxazole at 55.5%.  The sensitivity rates of S. aureus to various antibiotics varied from 22.2% to 59.3%. The antibiotic susceptibility pattern of the isolated Klebsiella pneumoniae (n=9) is displayed in Table 11. Amoxicillin, augmentin, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, co-trimoxazole, and gentamicin did not work at all on the Klebsiella pneumoniae isolates. Klebsiella pneumoniae has a 33.3% sensitivity rate to amikacin and a 33.3% sensitivity rate to ciprofloxacin.

Table 1: Age distribution of maxillofacial fracture patients treated with devices in 48 hospitals (n = 30).

Table 2: Sex distribution of maxillofacial fracture patients treated with devices in 48 hospitals (n = 30).

Table 3: Causes and mode of occurrence of maxillofacial fractures in patients treated with devices in 48 hospitals (n = 30).

Table 4: The types of fractures among head injury in patients treated with devices in 48 hospitals (n = 30).

Table 5: The sites of fractures among head injury in patients treated with devices in 48 hospitals (n = 30).

Table 6: Managements of infected hardware and types of hardware removal in patients treated with devices in 48 hospitals (n = 30).

Table 7: Clinical examination of fracture patients treated with devices in 48 hospitals (n = 30).

Table 8: Surgical managements for fracture patients treated with devices in 48 hospitals (n = 30).

Table 9: postoperative bacterial infections from Site of surgery in fracture patients treated with devices in 48 hospitals (n = 30).

Table 10: Antimicrobial susceptibility pattern of the isolated Staphylococcus aureus (n=27)

Table 11: Antimicrobial susceptibility pattern of the isolated Klebsiella pneumoniae (n=9).

The prevalence of maxillofacial injuries has increased in both urban and rural regions, and both industrialized and developing nations have seen a shift in this trend [24]. RTA has been identified as the primary cause of maxillofacial injuries in underdeveloped nations [26], whereas interpersonal violence has been identified as the primary cause in affluent nations [25]. Epidemiological assessments are said to be more precisely necessary for the execution of preventative measures and the efficacy of treatment. Additionally, coordinated, recurring, Men were more impacted  than women in this study, which is more than the ratio of 4.6:1 reported in Bulgaria (Bakardjiev and Pechalova); [27] in China (Mijiti et al.); [28] in Jordan; 3:1 (Bataineh); [29] and 2.1:1 in an Austrian study (Gassner et al.). [30]. Additionally, this ratio was larger than what was reported in several Saudi research; in one study, it was 4.8:1 (Rabi and Khateery) [31], while in another, it was 4.4:1 (Al-Masri et al.) in Jeddah. [32]. Conversely, this ratio was lower than the Indian report. In the southern part of Saudi Arabia, in Abha City (Al-Masri) [32], the ratio was reported to be 10:1, while in Jeddah (Jan et al.), [35], it was 6:1. Shanker et al. [33] and Motamedi et al. [34] recorded an 8:1 ratio. This difference may be related to cultural reasons. In the war in Yemen, women are completely prohibited from participating in combat, while men participate in the war. Gunshot wounds accounted for 50% of all cases in the current research, making them the most prevalent cause. Traffic accidents (20%), bomb blasts (16.7%), and pathological fractures (13.3%) were next in line. There were no documented instances of falls from a height. In contrast to other findings in other countries (Brasileiro and Passeri; [36] Mijiti et al.; [28] Motamedi et al. [34]) and Saudi Arabia (Nwoku and Oluyadi; [37] Abdullah et al.; [38] Al-Masri [32], where road traffic accidents were the primary cause, the current study found that road traffic accidents were the second major cause of maxillofacial fractures. Gunshot wounds were the most frequent cause in the current study, but bomb blasts and assaults were the primary source of injuries in studies conducted in Germany (Schneider et al.), Bulgaria (Bakardjiev and Pechalova), Australia (Cabalag et al.), and [27]. [40] Gunshots are seen as a serious public health concern in Yemen because to the ongoing conflict and the rising number of gun owners there. Driver error was found to be the primary contributor to road accidents in Yemen, primarily due to underage driving. Alcohol and drug use are not common causes of road accidents, as these substances are prohibited in Yemen. In the current study, traffic accidents accounted for 20% of the total causes of road accidents, with human error and vehicle mechanical failures being the primary causes. Therefore, in light of the findings of this study, as well as previous similar research conducted in other regions of Yemen, reducing road accidents requires strict enforcement of the law and national public awareness initiatives in Yemen. A continuous educational program is required to inform treating physicians about the recent use of aggressive treatment with appropriate antibiotics to prevent the occurrence of such cases. It is also important to note that the four cases of pathological mandibular fractures that were reported were caused by chronic osteomyelitis. In the current study, the locations of head injuries in patients treated with the device were identified; all fractures were mandibular. The prevalent mandibular fracture in our study is similar to other findings reported in other parts of the world (Brasileiro and Passeri; [36] Bakardjiev and Pishalova; [27] Megeti et al. [28], as well as some Middle Eastern countries (Motamedi et al. [34]), and Saudi Arabia (Abdullah et al. [38] Al-Masry [32]). However, these findings are inconsistent with those from Australia (Cabalag et al. [39]), which reported that the majority of patients suffered orbital fractures, a study in Germany (Schneider et al. [40]), where midfacial fractures with orbital floor injury were the most common, and a Saudi study at the Armed Forces Hospital in Riyadh (Nwoku and Oluyadi) [37], which reported that midfacial fractures were significantly higher than mandibular fractures. The difference in the affected bone may be related to the different causes reported in different studies in which gunshot was the most cause in the current study. The mandibular body fractures were the most commonly reported broken portion of the maxillofacial bones in this investigation, which is consistent with the findings of Haug et al. [6] According to a different research by Mijiti et al. [28], following mandibular body fractures, symphysis was the second most common location for mandibular fractures. In one research, Brasileiro and Passeri found that the most common locations of mandibular fractures were condylar fractures followed by symphysis fractures [36], whereas Motamedi et al. found that the most common sites were symphysis–parasymphysis fractures followed by condylar fractures [34]. The mechanism and direction of the impact at the moment of the accident may be responsible for this variation in the most afflicted area. Open reduction internal fixation (ORIF) was performed for the majority of patients in the current study (60%). This is similar to the results of a study in India (Bali et al.), [7] who reported that 62.2% of affected patients were treated with ORIF; and in China (Meghetti et al.), [28] the percentage was 62.4%. Of the 1024 cases retrospectively studied by Brasileiro and Passeri [36] in Brazil, 48% were treated conservatively and approximately another 48% were treated surgically, primarily with ORIF. Conversely, closed reduction was the most common treatment method in several other studies (Bataine; [29] Bakardjiev and Pichalova [27]). According to this study, S. aureus was the most often isolated species (90%) in the study. The results are greater than those of studies in Ethiopia, where the percentages of S. aureus were 33.3% [16] and 26.2% [18], while the research in Uganda showed that K. pneumonia was the most common isolate, with a 50% rate [41]. Variations in common hospital-acquired infections, as well as policies and recommendations for infection prevention and management among nations and wound sites, may be the cause of this discrepancy in the distribution of bacterial species. The Staphylococcus aureus isolates in this investigation were fully ineffective against Amoxicillin, Augmentin, Aztreonam, Cefotaxime, Cefoxitin, Ceftazidime, Piperacillin, Ceftriaxone, and Doxycycline. With a 100% sensitivity rate against S. aureus, vancomycin was the most effective antibiotic. The next highest sensitivity rate was 88.9% for Teicoplanin, followed by 55.5% for Tobramycin, 66.7% for Gentamicin, and 55.5% for Co-trimoxazole. These antibiotics were found to be reasonably effective in treating S. aureus-caused SSIs, which is in line with a study that was previously published in Yemen by Alhadi et al. [42], Al-Makdad et al. [21], and in Ethiopia by Gelaw et al. [43]. Conversely, the AlShami et al. investigation found that these medications were less effective [44]. It is possible that the increase in antibiotic resistance brought on by the irrational use of anti-infective medications, insufficient controls to prevent the spread of infections, variations in common hospital-acquired pathogens, and the acquisition of organisms resistant to antibiotics are linked to both the duration of exposure to these microorganisms and the presence of risk factors. Additionally, the current investigation showed that the Klebsiella pneumoniae isolates were completely unaffected by amoxicillin, augmentin, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, co-trimoxazole, and gentamicin. Amikacin and ciprofloxacin sensitivity rates for Klebsiella pneumoniae are 33.3% and 33.3%, respectively. These findings contrast nearly entirely from those previously published in Yemen [21,45–49], where the sensitivity rates for the aforementioned investigations were provided. The current study demonstrates that Gram-negative bacteria, especially Klebsiella pneumoniae, are alarmingly resistant to the polyclonal antibiotics Amoxicillin, augmentin, cefotaxime, cefoxitin, ceftazidime, ceftriaxone, co-trimoxazole, and gentamicin (100%). This resistance rate was higher than that of earlier studies carried out in Yemen [45–49]. This might be because the development and spread of resistance are mostly caused by the experimental treatment of isolates, the haphazard and frequent use of these antibiotics by inexperienced practitioners, and the absence of antibiotic usage standards [21,44,50].

The study found that males were 100% more likely to suffer mandibular fractures, with the majority of cases occurring in those aged 20 to 24 (56.7%). Gunshot wounds were the most common cause. The most commonly isolated bacteria was Staphylococcus aureus, with a very high rate of multidrug resistance. Vancomycin was found to be the most reliable drug for treating Staphylococcus aureus infections.

The main limitation of this study was the small sample size included with short -term follow-up.

The accompanying author can provide the empirical data that were utilized to support the study's conclusions upon request.

There are no conflicts of interest in regard to this project.

Dr. Hend Naji Al-Sabri: Formal analysis, conceptualization, data organization, and clinical and laboratory examinations to obtain a board’s degree in Oral and Maxillofacial Surgery. Lutf Mohammed Al-Rahbi: conceptualization, data organization, supervised the work. Hassan Abdulwahab Al-Shamahy reviewed the article, and approved the final version.