Oral Infection Caused by Stenotrophomonas maltophilia: A Rare Presentation of an Emerging Opportunistic Pathogen

Oral colonization of antimicrobial-resistant bacteria in home health care participants and their association with oral and systemic status

Antimicrobial-resistant bacteria (ARBs) are serious global threat because they make it difficult to treat infections with antibiotics. Recently, it has been demonstrated that ARBs are isolated from the oral cavities of elderly individuals in long-term care facilities. Because oral ARBs can cause systemic diseases such as bacteraemia and aspiration pneumonia, more attention must be given to protect the overall health of elderly people. To understand the prevalence of oral ARBs, more studies are needed in addition to previous studies. In this study, we investigated oral ARBs in elderly people receiving home health care (HHC) who had different lifestyles as residents in long-term care facilities. Among 98 HHC participants, Staphylococcus aureus, including 8 methicillin-resistant S. aureus (MRSA) strains, was isolated from 31 participants (31.7%), and 3rd-generation cephalosporin-resistant gram-negative bacteria (GNARB) were isolated from 18 participants (17.8%). An analysis of the relationship between oral ARBs and clinical status revealed that S. aureus/MRSA isolation was correlated with denture condition, while GNARB isolation was correlated with tube feeding. This study is the first comprehensive analysis of ARB carriage in the oral cavities of elderly people in HHCs. These results demonstrate the potential risk of oral ARB carriage and the importance of infection control in HHCs.

ST88 ceftazidime-resistant Stenotrophomonas maltophilia is present in the saliva and gingival crevicular fluid of patients with periodontitis and AIDS from São Paulo State, Brazil

Stenotrophomonas maltophilia (S. maltophilia) is an intrinsically drug-resistant and biofilm-forming bacteria causing infections in immunocompromised humans. This study reports the isolation of five S. maltophilia strains from saliva and gingival crevicular fluid (GCF) of AIDS patients with periodontitis in São Paulo, Brazil, showing resistance to ceftazidime, strong biofilm formation capacity and a close genetic relationship. The presence of S. maltophilia strains in saliva and CGF of patients with AIDS and periodontitis is a concern for the presence and persistence of intrinsically resistant bacteria in the oral environment, enhancing the risk for the development of severe infections in immunocompromised patients.

Antibiotic resistance among Aerobic Gram-Negative Bacilli isolated from patients with oral inflammatory dysbiotic conditions-a retrospective study

Introduction

Aerobic gram-negative bacilli (AGNB) are not part of the resident oral microflora but are occasionally found in high abundance under inflammatory dysbiotic conditions at various oral niches. The aim of the present study was to investigate the identity and antibiotic susceptibility of AGNB isolated from patients in Sweden with mucosal lesions, periodontitis, and peri-implantitis, with special attention to antibiotic resistance and on the presence of phenotypic Extended Spectrum Beta-Lactamase (ESBL) isolates.

Materials and methods

Microbiolgical samples were harvested from 211 patients in total, experiencing mucosal lesions (N = 113), periodontitis (N = 62), or peri-implantitis (N = 36). The growth of AGNBs was semiquantified by selective and non-selective culture and the strains were isolated, identified, and tested for antibiotic susceptibility. A total of 251 AGNB strains, occurring in moderate to heavy growth (>100 CFU/ml sample), indicating a dysbiotic microbiota, were identified. The disc diffusion method was used for screening of the antibiotic susceptibility of the isolates. Phenotypic identification of ESBL isolates was based on resistance to ceftazidime and/or cefotaxime.

Results

The most commonly detected AGNB isolates in oral inflammatory dysbiotic conditions were fermentative species belonging to Enterobacteriaceae e.g. Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp, and the non-fermentative environmental Burkholderia cepacia, Pseudomonas spp., and Stenotrophomonas maltophilia. No clear trends were seen in frequency of the various species in samples from mucosal lesions, severe periodontitis, and peri-implantitis cases. The 138 Enterobacteriaceae isolates and 113 environmental AGNB isolated showed a high antibiotic resistance in general against antibiotics commonly used in dentistry (Amoxicillin, Amoxicillin + Clavulanic acid, Ampicillin, Clindamycin, Doxycycline, Erythromycin, Oxacillin, PenicillinV, and Tetracycline). The majority of these isolates were susceptible to ciprofloxacin. Ten isolates (4.1%) were phenotypically classified as ESBL positive. The ESBL isolates were predominantly found among isolates of S. maltophilia, while only one ESBL positive isolate was found among Enterobacteriaceae.

Conclusions

Phenotypically identified ESBL isolates can occasionally be present among oral AGNB strains isolated in abundance from the dysbiotic microbiota occurring in cases with oral mucosal lesions, severe periodontitis, or peri-implantitis.

Association of periodontal therapy, with inflammatory biomarkers and complications in COVID-19 patients: a case control study

BACKGROUND

In previous studies, COVID-19 complications were reported to be associated with periodontitis. Accordingly, this study was designed to test the hypothesis that a history of periodontal therapy could be associated with lower risk of COVID-19 complications.

METHODS

A case-control study was performed using the medical health records of COVID-19 patients in the State of Qatar between March 2020 and February 2021 and dental records between January 2017 and December 2021. Cases were defined as COVID-19 patients who suffered complications (death, ICU admissions and/or mechanical ventilation); controls were COVID-19 patients who recovered without major complications. Associations between a history of periodontal therapy and COVID-19 complications were analysed using logistic regression models adjusted for demographic and medical factors. Blood parameters were compared using Kruskal-Wallis test.

RESULTS

In total, 1,325 patients were included. Adjusted odds ratio (AOR) analysis revealed that non-treated periodontitis was associated with significant risk of need for mechanical ventilation (AOR = 3.91, 95% CI 1.21-12.57, p = 0.022) compared to periodontally healthy patients, while treated periodontitis was not (AOR = 1.28, 95% CI 0.25-6.58, p = 0.768). Blood analyses revealed that periodontitis patients with a history of periodontal therapy had significantly lower levels of D-dimer and Ferritin than non-treated periodontitis patients.

CONCLUSION

Among COVID-19 patients with periodontal bone loss, only those that have not received periodontal therapy had higher risk of need for assisted ventilation. COVID-19 patients with a history of periodontal therapy were associated with significantly lower D-dimer levels than those without recent records of periodontal therapy.

CLINICAL RELEVANCE

The fact that patients with treated periodontitis were less likely to suffer COVID-19 complications than non-treated ones further strengthen the hypothesis linking periodontitis to COVID-19 complications and suggests that managing periodontitis could help reduce the risk for COVID-19 complications, although future research is needed to verify this.

Clinical challenges treating Stenotrophomonas maltophilia infections: an update

Stenotrophomonas maltophilia is a non-fermenting, Gram-negative bacillus that has emerged as an opportunistic nosocomial pathogen. Its intrinsic multidrug resistance makes treating infections caused by S. maltophilia a great clinical challenge. Clinical management is further complicated by its molecular heterogeneity that is reflected in the uneven distribution of antibiotic resistance and virulence determinants among different strains, the shortcomings of available antimicrobial susceptibility tests and the lack of standardized breakpoints for the handful of antibiotics with in vitro activity against this microorganism. Herein, we provide an update on the most recent literature concerning these issues, emphasizing the impact they have on clinical management of S. maltophilia infections.

Advances in the Microbiology of Stenotrophomonas maltophilia

Stenotrophomonas maltophilia is an opportunistic pathogen of significant concern to susceptible patient populations. This pathogen can cause nosocomial and community-acquired respiratory and bloodstream infections and various other infections in humans. Sources include water, plant rhizospheres, animals, and foods. Studies of the genetic heterogeneity of S. maltophilia strains have identified several new genogroups and suggested adaptation of this pathogen to its habitats. The mechanisms used by S. maltophilia during pathogenesis continue to be uncovered and explored. S. maltophilia virulence factors include use of motility, biofilm formation, iron acquisition mechanisms, outer membrane components, protein secretion systems, extracellular enzymes, and antimicrobial resistance mechanisms. S. maltophilia is intrinsically drug resistant to an array of different antibiotics and uses a broad arsenal to protect itself against antimicrobials. Surveillance studies have recorded increases in drug resistance for S. maltophilia, prompting new strategies to be developed against this opportunist. The interactions of this environmental bacterium with other microorganisms are being elucidated. S. maltophilia and its products have applications in biotechnology, including agriculture, biocontrol, and bioremediation.