The microbiology of paranasal sinus infections: diagnosis and management

Complications of frontal sinus fractures

Frontal sinus fracture represents 5 to 12% of all maxillofacial fractures. Because of the anatomic position of the frontal sinus and the enormous amount of force required to create a fracture in this area, these injuries are often devastating and associated with other trauma. Associated injuries include skull base, intracranial, ophthalmologic, and maxillofacial. Complications should be categorized to address these four areas as well as the skin-soft tissue envelope, muscle, and bone. Other variables that should be examined are age of the patient, gender, mechanism of injury, fracture pattern, method of repair, and associated injuries. Management of frontal sinus fractures is so controversial that the indications, timing, method of repair, and surveillance remain disputable among several surgical specialties. The one universal truth that is agreed upon is that all patients undergoing reconstructive surgery of the frontal sinus have a lifelong risk for delayed complications. It is hoped that when patients do experience the first symptoms of a complication, they seek immediate medical attention and avoid potentially life-threatening situations and the need for crippling or disfiguring surgery. The best way to facilitate this is through long-term follow-up and routine surveillance.

Bacteria detected by culture and 16S rRNA sequencing in maxillary sinus samples from intensive care unit patients

OBJECTIVES/HYPOTHESIS

In critically ill patients, the occurrence of artificial ventilation-acquired sinus disease is common. A possible sinus bacterial infection is occult and is combined with diagnostic difficulties. Culture as a method has limited capacity to verify the presence of bacteria and leaves unanswered the question of a possible infective agent because bacteria are difficult to grow when killed or suppressed by current antibiotic therapy. Hitherto unidentified micro-organisms are also possible in the microenvironments of maxillary sinuses.

STUDY DESIGN

Prospective case series.

METHODS

Twenty maxillary sinus samples (17 aspirates and 3 lavages) from nine critically ill patients with possible infectious disease were investigated by broad-range 16S rRNA polymerase chain reaction followed by sequencing. These results were compared with the previous culture results from gingiva (passage route), maxillary sinus absorption, and mucosa samples.

RESULTS

The contaminations were rare (2 of 20) and corresponded well to culture results. One previously undiagnosed bacterium was found. Two aspirates were negative on both culture and polymerase chain reaction, whereas the corresponding maxillary sinus mucosal cultures had been positive.

CONCLUSIONS

Applying a low-contamination maxillary sinuses sampling technique makes 16S rRNA sequencing clinically useful. The polymerase chain reaction and culture results were generally comparable. However, by polymerase chain reaction, bacteria were found that were missed by culturing. Some aspirates were free of bacterial remnants on 16S rRNA polymerase chain reaction, but corresponding mucosal cultures were positive. This could indicate that infection is induced within the tissue. It also indicates that infectious agents introduced into the sinuses may have routes other than the ostium. Further clinical use of 16S rRNA sequencing is required to enlarge our knowledge in applied microbiology and paranasal sinus disease.

The biopharmaceutical aspects of nasal mucoadhesive drug delivery

Nasal drug administration has frequently been proposed as the most feasible alternative to parenteral injections. This is due to the high permeability of the nasal epithelium, allowing a higher molecular mass cut-off at approximately 1000 Da, and the rapid drug absorption rate with plasma drug profiles sometimes almost identical to those from intravenous injections. Despite the potential of nasal drug delivery, it has a number of limitations. In this review, the anatomy and physiology of the nasal cavity, as well as ciliary beating and mucociliary clearance as they relate to nasal drug absorption, are introduced. The rationale for nasal drug delivery and its limitations, some factors that influence nasal drug absorption, and the experimental models used in nasal drug delivery research are also reviewed. Nasal mucoadhesion as a promising method of nasal absorption enhancement is discussed, and factors that influence mucoadhesion, as well as safety of nasal mucoadhesive drug delivery systems are reviewed in detail. Nasal drug administration is presently mostly used for local therapies within the nasal cavity. Anti-allergic drugs and nasal decongestants are the most common examples. However, nasal drug administration for systemic effects has been practised since ancient times. Nasally-administered psychotropic drugs by native Americans, the use of tobacco snuffs, and nasal administration of illicit drugs such as cocaine are all well known (Illum & Davis 1992). Nowadays, the nasal cavity is being actively explored for systemic administration of other therapeutic agents, particularly peptides and proteins (Illum 1992; Edman & Björk 1992), as well as for immunization purposes (Lemoine et al 1998). To better understand the basis for nasal drug absorption and factors that can influence it, a brief review of the anatomy and physiology of the nose is appropriate.

Bacteriology of the maxillary and ethmoid sinuses in chronic sinusitis

The bacteriology of chronic sinusitis was studied by using swab and mucosal specimens from both the maxillary and ethmoid sinuses. The specimens of the maxillary sinus were taken through translabial antroscopy. The specimens of the ethmoid sinus were taken after removing the ethmoid bulla during functional endoscopic sinus surgery (FESS). Eighty-six samples of each type of specimen were collected. Among the maxillary sinus samples, the culture rate was 60.5 per cent from the swab specimens and 36 per cent from the mucosal specimens. Among the ethmoid sinus samples, the culture rate was 58.1 per cent from the swab specimens and 75.6 per cent from the mucosal. The p-value by the Chi-Square test is higher than 0.01 (p = 0.015). As there were more isolates of Staphylococcus epidermidis from the mucosal specimens, they are not a better choice of specimen for sampling the ethmoid sinus than a swab specimen.

Possible errors in diagnosis of bacterial sinusitis in tracheal intubated patients

Bacterial sinusitis is recognized as a complication of prolonged nasotracheal intubation. Verification of the diagnosis, however, requires culture findings from a "true" sample from the maxillary antrum. A "true" antral sample can only be obtained after passing either the nasal or oral mucosae with their rich aerobic and anaerobic bacterial flora. No properly controlled study has been made into the problem of contaminated samples in bacterial sinusitis complicating prolonged nasotracheal intubation. The design of the study was a case series in an intensive care unit. The patients had either had endotracheal tube or tracheal cannula for seven days or were septic, having an endothracheal tube or a tracheal cannula and therefore due to an investigation of infection foci. Antral cultures obtained via the canine fossa were compared with oral cultures to exclude the contribution of oral bacterial contamination and thereby to improve the reliability of diagnosis based on culture results. The contamination rate was lowered significantly from 67% to 5% when an area of free bone was prepared in the canine fossa thus avoiding instrument contact with the oral mucosa. A high contamination risk can be dealt with by adjusting the technique of sampling thereby increasing the culture reliability.

Evaluation of the microbiology of chronic ethmoid sinusitis

In a prospective study, patients with the diagnosis of chronic ethmoid sinusitis were evaluated microbiologically by using biopsy specimens of the ethmoid sinus mucosa. Microbiology cultures were performed on 94 specimens from 59 patients. Staphylococcus aureus and members of the family Enterobacteriaceae were the most frequent classical pathogenic bacteria isolated. Coagulase-negative staphylococci were the most common overall isolates. Streptococcus pneumoniae and Haemophilus influenzae were infrequent isolates. No anaerobes, viruses, or Chlamydia trachomatis organisms were identified. Results of this study showed organism isolation frequencies different from those found in other studies of chronic sinusitis reported in the literature. The predominance of S. aureus and members of the family Enterobacteriaceae could have an effect on the antimicrobial therapy for chronic ethmoid sinusitis.