Microbiology of parapharyngeal abscesses in adults: in search of the significant pathogens

Penicillin concentrations in oropharyngeal and frontal sinus tissue following enteral and intravenous administration measured by microdialysis in a porcine model

BACKGROUND

Penicillin may be administered enterally or intravenously for the treatment of bacterial infections within the oropharynx and the frontal sinuses. We aimed to assess and compare penicillin concentrations in oropharyngeal and frontal sinus tissues following enteral and intravenous administration in a porcine model.

METHOD

Twelve pigs were randomized to receive either enteral (0.8 g Penicillin V) or intravenous (1.2 g Penicillin G) penicillin. Microdialysis was used for sampling in oropharyngeal and frontal sinus tissues during a six-hour dosing interval. In addition, plasma samples were collected. The primary endpoints were time with drug concentration above the minimal inhibitory concentration (T>MIC) for two MIC targets: 0.125 (low target) and 0.5 (high target) μg/mL (covering Group A Streptococci, Fusobactarium necrophorum, Streptococcus pneumoniae and Hemophilus influenza) and attainment of these treatment targets for ≥50 % T>MIC.

RESULTS

For both the low and high MIC targets, intravenous administration resulted in higher T>MIC in oropharyngeal and frontal sinus tissues compared to enteral administration. In oropharyngeal tissue, the treatment target (≥50 % T>MIC) was achieved for both the low target (96 %) and high target (68 %) when penicillin was administrated intravenously. In frontal sinus tissue, the treatment target was reached for the low target (70 %), but not the high target (35 %) when administered intravenously. None of the two tissues reached the treatment targets when penicillin was administered enterally.

CONCLUSION

Intravenous administrated penicillin in standard dosage is superior to enteral administration of penicillin in standard dosage in achieving clinically important T>MIC as the majority of targets were achieved following intravenously administration, while none of the targets were achieved following enteral administration. These results support the general notion of higher tissue concentrations following intravenous compared to enteral administration.

The impact of social restrictions on the incidence and microbiology of peritonsillar abscess: a retrospective cohort study

OBJECTIVES

We aimed to explore the impact of social distancing on the incidence and microbiology of peritonsillar abscess (PTA).

METHODS

We performed a cross-sectional analysis of all patients with PTA and their microbiological findings in the 2 years preceding versus the 2 years following the COVID-19 lockdown in Denmark (11 March 2020), who were admitted to the Ear-Nose-Throat Department, Aarhus University Hospital. Age-stratified population data for the catchment area were obtained from Statistics Denmark.

RESULTS

The annual incidence rate was significantly higher in the 2-year period before (21.8 cases/100 000 inhabitants) compared with after (14.9 cases/100 000) the lockdown (p < 0.001). The number of cases with growth of Streptococcus pyogenes was significantly higher in the period before (n = 67) compared with after (n = 28) the lockdown (p < 0.001), whereas the number of cases positive for Fusobacterium necrophorum (n = 60 vs. n = 64) and streptococcus anginosus group (SAG) (n = 37 vs. n = 43) were stabile (p 0.79 and p 0.58, respectively). The relative prevalence of S. pyogenes was significantly higher in the period before (67/246 cultures, 27%) compared with after (28/179, 16%) the lockdown (p 0.007). On the contrary, the relative prevalence of F. necrophorum and SAG is significantly lower before (60/246, 24% and 37/246, 15%) compared with after (64/179, 36% and 43/179, 24%) the lockdown (p 0.013 and p 0.023).

DISCUSSION

Social distancing had a significant impact on the incidence and microbiology of PTA. Our findings suggest that S. pyogenes-positive PTA is highly related to direct social interaction, and represents a contagious pathogen. By contrast, PTA development caused by F. necrophorum and SAG is unrelated to direct social interaction and may be derived from flora imbalance.

Nasal Endoscopic Incision and Drainage Transnasal Retropterygoid Approach to Upper Parapharyngeal Abscess: A Novel Technique

Parapharyngeal infection is a well-known disease of otorhinolaryngologists. Rapid onset, short duration, severe symptoms, and manifestations such as sore throat and dysphagia are common characteristics treated primarily by surgical incision and drainage. Traditional surgical approaches encompass endoscopic transoral/nasal, transparotid, transcervical, or a combination thereof. We report a novel technique of nasal endoscopic incision and drainage transnasal retropterygoid approach to an upper parapharyngeal abscess. This report presents a case of a 14-year-old man presented with severe right neck and head pain, who was found to have an upper parapharyngeal abscess during a nasal endoscopic parapharyngeal exploration via a retropterygoid approach. The intraoperative frozen section revealed chronic mucosal inflammation and mild to moderate dysplasia of the squamous epithelium, but no carcinoma.

Bacterial findings in patients referred to hospital for the treatment of acute tonsillitis with or without peritonsillar phlegmon

BACKGROUND

The vast majority of patients with acute tonsillitis (AT) are managed in general practice. However, occasionally patients are referred to hospital for specialized management because of aggravated symptoms and/or findings suggestive of peritonsillar involvement. No prospective studies have been conducted aiming to investigate the prevalent and significant microorganisms in this highly selected group of patients. We aimed to describe the microbiological findings of acute tonsillitis with or without peritonsillar phlegmon (PP) in patients referred for hospital treatment and to point out potential pathogens using the following principles to suggest pathogenic significance: (1) higher prevalence in patients compared to healthy controls, (2) higher abundance in patients compared to controls, and (3) higher prevalence at time of infection compared to time of follow up.

METHODS

Meticulous and comprehensive cultures were performed on tonsillar swabs from 64 patients with AT with (n = 25) or without (n = 39) PP and 55 healthy controls, who were prospectively enrolled at two Danish Ear-Nose-Throat Departments between June 2016 and December 2019.

RESULTS

Streptococcus pyogenes was significantly more prevalent in patients (27%) compared to controls (4%) (p < 0.001). Higher abundance was found in patients compared to controls for Fusobacterium necrophorum (mean 2.4 vs. 1.4, p = 0.017) and S. pyogenes (mean 3.1 vs. 2.0, p = 0.045) in semi-quantitative cultures. S. pyogenes, Streptococcus dysgalactiae, and Prevotella species were significantly more prevalent at time of infection compared to follow up (p = 0.016, p = 0.016, and p = 0.039, respectively). A number of species were detected significantly less frequently in patients compared to controls and the mean number of species was significantly lower in patients compared to controls (6.5 vs. 8.3, p < 0.001).

CONCLUSIONS

Disregarding Prevotella spp. because of the prevalence in healthy controls (100%), our findings suggest that S. pyogenes, F. necrophorum, and S. dysgalactiae are significant pathogens in severe AT with or without PP. In addition, infections were associated with reduced diversity (dysbacteriosis).

TRIAL REGISTRATION

The study is registered in the ClinicalTrials.gov protocol database (# 52,683). The study was approved by the Ethical Committee at Aarhus County (# 1-10-72-71-16) and by the Danish Data Protection Agency (# 1-16-02-65-16).

Efficacy of the Endolysin-Based Antibacterial Gel for Treatment of Anaerobic Infection Caused by Fusobacterium necrophorum

Abscess formation is a common complication of severe life-threatening infections caused by obligate anaerobes. Fusobacterium necrophorum is among the frequently detected anaerobic pathogens from clinical specimens associated with liver abscesses, skin and soft tissue infections, or oral abscesses. The antimicrobial therapy for this kind of infection needs to be optimized. Here, we examined the possibility of treating F. necrophorum-induced abscess wound infections with candidate therapeutics based on three endolysins with activity against a broad spectrum of aerobe Gram-negative pathogens. Antibacterial gel containing three Gram-negative bacteria-targeting endolysins, LysAm24, LysAp22, and LysECD7, was formulated for topical use. Abscess formation was induced in rabbits with F. necrophorum and caused systemic infection. The survival and lifespan of the animals, general parameters, and biochemical and hematological blood tests were analyzed to assess the effectiveness of the gel treatment for the wound infection. The administration of the investigated gel twice per day for 5 days resulted in less acute inflammation, with decreased leukocytes and segmented neutrophils in the blood, retardation of infection progression, and an almost two-fold increase in the lifespan of the animals compared to the placebo group. The results indicate that endolysin-based therapy is an effective approach to treat anaerobic bacterial infections. The use of endolysins as independent pharmaceuticals, or their combination with antibiotics, could significantly reduce the development of complications in infectious diseases caused by sensitive bacterial species.

Clinical evaluation of antibiotic regimens in patients with surgically verified parapharyngeal abscess: a prospective observational study

PURPOSE

We aimed to evaluate the effectiveness of different antibiotic regimens for the treatment of parapharyngeal abscess (PPA) and characterize patients, who suffered potentially preventable complications (defined as death, abscess recurrence, spread of infection, or altered antibiotic treatment because of insufficient progress).

METHODS

Sixty adult patients with surgically verified PPA were prospectively enrolled at five Danish Ear-nose-throat departments.

RESULTS

Surgical treatment included internal incision (100%), external incision (13%), and tonsillectomy (88%). Patients were treated with penicillin G ± metronidazole (n = 39), cefuroxime ± metronidazole (n = 16), or other antibiotics (n = 5). Compared to penicillin-treated patients, cefuroxime-treated patients were hospitalized for longer (4.5 vs 3.0 days, p = 0.007), were more frequently admitted to intensive care (56 vs 15%, p = 0.006), underwent external incision more frequently (31 vs 5%, p = 0.018), and suffered more complications (50 vs 18%, p = 0.022), including re-operation because of abscess recurrence (44 vs 3%, p < 0.001). Nine patients suffered potentially preventable complications. These patients displayed significantly higher C-reactive protein levels, received antibiotics prior to admission more frequently, underwent external incision more commonly, and were admitted to intensive care more frequently compared to other patients.

CONCLUSION

The majority of patients with PPA were effectively managed by abscess incision, tonsillectomy, and penicillin G ± metronidazole. Cefuroxime-treated patients were more severely ill at time of admission and had worse outcome compared to penicillin-treated patients. We recommend penicillin G + metronidazole as standard treatment for patients with PPA, but in cases with more risk factors for potentially preventable complications, we recommend aggressive surgical and broadened antibiotic therapy, e.g. piperacillin-tazobactam.