Analysis of Microorganism Colonization, Biofilm Production, and Antibacterial Susceptibility in Recurrent Tonsillitis and Peritonsillar Abscess Patients.

Background: Despite the widespread use of antibiotics to treat infected tonsils, episodes of tonsillitis tend to recur and turn into recurrent tonsillitis (RT) or are complicated by peritonsillar abscesses (PTAs). The treatment of RT and PTAs remains surgical, and tonsillectomies are still relevant. Materials and methods: In a prospective, controlled study, we analyzed the bacteria of the tonsillar crypts of 99 patients with RT and 29 patients with a PTA. We performed the biofilm formation and antibacterial susceptibility testing of strains isolated from study patients. We compared the results obtained between patient groups with the aim to identify any differences that may contribute to ongoing symptoms of RT or that may play a role in developing PTAs. Results: The greatest diversity of microorganisms was found in patients with RT. Gram-positive bacteria were predominant in both groups. Candida species were predominant in patients with a PTA (48.3% of cases). Irrespective of patient group, the most commonly isolated pathogenic bacterium was S. aureus (in 33.3% of RT cases and in 24.14% of PTA cases). The most prevalent Gram-negative bacterium was K. pneumoniae (in 10.1% of RT cases and in 13.4% of PTA cases). At least one biofilm-producing strain was found in 37.4% of RT cases and in 27.6% of PTA cases. Moderate or strong biofilm producers were detected in 16 out of 37 cases of RT and in 2 out of 8 PTA cases. There was a statistically significant association found between the presence of Gram-positive bacteria and a biofilm-formation phenotype in the RT group and PTA group (Pearson χ2 test, p < 0.001). S. aureus and K. pneumoniae strains were sensitive to commonly used antibiotics. One S. aureus isolate was identified as MRSA. Conclusions: S. aureus is the most common pathogen isolated from patients with RT, and Candida spp. are the most common pathogens isolated from patients with a PTA. S. aureus isolates are susceptible to most antibiotics. Patients with RT more commonly have biofilm-producing strains, but patients with a PTA more commonly have biofilm non-producer strains. K. pneumoniae does not play a major role in biofilm production.

Evaluation of Staphylococcus aureus Colonization in Adult Patients Undergoing Tonsillectomy for Recurrent Tonsillitis.

BACKGROUND AND OBJECTIVES: Staphylococcus aureus (S. aureus) is often recovered from the pharynx. However, the role of this pathogen in the etiology of tonsillar inflammation is still unclear and complicated due to frequent carriage of S. aureus. The aim of the study was to evaluate the frequency and the clinical importance of S. aureus colonization and biofilm production ability in patients with recurrent tonsillitis (RT) using patient samples from tonsillar crypts during tonsillectomy, and from the throat, nasal cavity, and armpits after tonsillectomy. MATERIALS AND METHODS: A case series study was carried out at a tertiary referral center among 16 patients diagnosed with RT who were undergoing tonsillectomy. Samples from tonsillar crypts were obtained during tonsillectomy, and samples from the throat, nasal cavity, and armpit were obtained a year after surgery. An evaluation of S. aureus incidence, biofilm formation, and antibacterial susceptibility was performed. RESULTS: During tonsillectomy, 16 strains of S. aureus were isolated from 16 patients, while 15/16 S. aureus strains were biofilm producers. A year after tonsillectomy, 8 S. aureus strains were isolated from 6 out of 16 patients, while 6/8 S. aureus strains were biofilm producers. After tonsillectomy, 3 patients showed S. aureus in throat culture. CONCLUSIONS: In 10/16 cases S. aureus was the causative agent of RT, in 4/16 cases patients had a predisposition to colonization of S. aureus, and in 2/16 cases S. aureus was a part of the patients` oral microbiome. Tonsillectomy results in less frequent isolation of S. aureus strains.

S. aureus and K. pneumoniae on the Surface and within Core of Tonsils in Adults with Recurrent Tonsillitis.

Background and Objectives: Recurrent tonsillitis is an infection of the palatine tonsils. Samples for microbiological testing are usually obtained from the inflamed surface of the tonsils. Colonizing the surface bacteria does not always correlate with pathogens causing recurrent tonsillitis and there is no consensus or this in research studies. The aim of the study was to compare whether Staphylococcus aureus (S. aureus) and Klebsiella pneumoniae (K. pneumoniae) differ when isolated from the tonsillar surface or tonsillar crypts in patients with recurrent tonsillitis. Materials and Methods: a case series study was conducted at a tertiary referral center among 25 patients diagnosed with recurrent tonsillitis. An evaluation of S. aureus and K. pneumoniae incidence, biofilm formation and antibacterial susceptibility was performed. Results: There was a statistically significant association between surface and punch biopsy samples for S. aureus (Fisher's Exact test p = 0.004) and K. pneumoniae (Fisher's Exact test p < 0.001). A McNemar test did not reveal a statistically significant association. Although the antibacterial resistance profile was not broad, five out of nine S. aureus isolates were biofilm producers and four out of five K. pneumoniae isolates were biofilm producers. Conclusions: Surface and core cultures of tonsils are comparable with a differing incidence between the surface and the punch biopsy cultures for S. aureus and K. pneumoniae. A larger quantity of bacteria exist in surface samples suggesting that a biopsy sample may be less challenging in evaluating recurrent tonsillitis. We recommend that antibacterial susceptibility results are considered alongside the biofilm-forming potential of isolated bacteria.