Investigation of oral opportunistic pathogens in independent living elderly Japanese

Effect of perioperative oral management on postoperative bloodstream infection in heart valve surgery patients

OBJECTIVE

There is a well-known relationship between oral hygiene and infective endocarditis. Epidemiological evidence regarding perioperative oral management (POM) for cancer surgery has been accumulated, but this evidence is not sufficient for cardiac surgery. Therefore, our purpose was to investigate whether POM can prevent postoperative complications in patients undergoing heart valve surgery.

SUBJECTS AND METHODS

Using single-arm medical information, we retrospectively enrolled 301 patients who underwent heart valve surgery between April 2010 and March 2019. The patient background was adjusted by the propensity score (PS). We then analyzed the impact of POM on postoperative bloodstream infection (PBSI), postoperative pneumonia, and mortality using PS inverse probability of treatment weighting (IPTW).

RESULTS

IPTW revealed that the POM group had a lower incidence of PBSI than the control group, with an odds ratio of 0.316 (p = 0.003). The mortality in the POM group was significantly lower than that in the control group (p = 0.023). Fourteen patients died in the present study and 6 of them were infection-related.

CONCLUSIONS

POM was significantly associated with decreased incidence of PBSI and mortality. The results suggest that POM is beneficial for the prevention of PBSI and mortality in patients undergoing heart valve surgery.

Biocompatibile nanofiber based membranes for high-efficiency filtration of nano-aerosols with low air resistance

Particulate matter (PMs) from combustion emissions (traffic, power plant, and industries) and the novel coronavirus (COVID-19) pandemic have recently enhanced the development of personal protective equipment against airborne pathogens to protect humans' respiratory system. However, most commercial face masks still cannot simultaneously achieve breathability and high filtration of PMs, bacteria, and viruses. This study used the electrospinning method with polyimide (PI) and polyethersulfone (PES) solutions to form a nanofiber membrane with low-pressure loss and high biocompatibility for high-efficiency bacteria, viruses, and nano-aerosol removal. Conclusively, the optimized nano-sized PI/PES membrane (0.1625 m²/g basis weight) exhibited conspicuous performance for the highest filtration efficiency towards PM from 50 to 500 nm (99.74 %), good filter quality of nano-aerosol (3.27 Pa^-1), exceptional interception ratio against 100-nm airborne COVID-19 (over 99 %), and non-toxic effect on the human body (107 % cell viability). The PI/PES nanofiber membrane required potential advantage to form a medical face mask because of its averaged 97 % BEF on Staphylococcus aureus filiation and ultra-low pressure loss of 0.98 Pa by referring ASTM F2101-01. The non-toxic PI/PES filters provide a new perspective on designing excellent performance for nano-aerosols from air pollution and airborne COVID-19 with easy and comfortable breathing under ultra-low air flow resistance.

Cotton and Surgical Face Masks in Community Settings: Bacterial Contamination and Face Mask Hygiene

During the current COVID-19 pandemic, the use of face masks has become increasingly recommended and even mandatory in community settings. To evaluate the risk of bacterial cross-contamination, this study analyzed the bacterial bioburden of disposable surgical masks and homemade cotton masks, and surveyed the habits and face mask preferences of the Flemish population. Using culture approaches and 16S rRNA gene amplicon sequencing, we analyzed the microbial community on surgical and/or cotton face masks of 13 healthy volunteers after 4 h of wearing. Cotton and surgical masks contained on average 1.46 × 10⁵ CFU/mask and 1.32 × 10⁴ CFU/mask, respectively. Bacillus, Staphylococcus, and Acinetobacter spp. were mostly cultured from the masks and 43% of these isolates were resistant to ampicillin or erythromycin. Microbial profiling demonstrated a consistent difference between mask types. Cotton masks mainly contained Roseomonas, Paracoccus, and Enhydrobacter taxa and surgical masks Streptococcus and Staphylococcus. After 4 h of mask wearing, the microbiome of the anterior nares and the cheek showed a trend toward an altered beta-diversity. According to dedicated questions in the large-scale Corona survey of the University of Antwerp with almost 25,000 participants, only 21% of responders reported to clean their cotton face mask daily. Laboratory results indicated that the best mask cleaning methods were boiling at 100°C, washing at 60°C with detergent or ironing with a steam iron. Taken together, this study suggests that a considerable number of bacteria, including pathobionts and antibiotic resistant bacteria, accumulate on surgical and even more on cotton face masks after use. Based on our results, face masks should be properly disposed of or sterilized after intensive use. Clear guidelines for the general population are crucial to reduce the bacteria-related biosafety risk of face masks, and measures such as physical distancing and increased ventilation should not be neglected when promoting face mask use.

Prevalence and Antimicrobial Susceptibility of Bacterial Pathogens in Ready-to-Eat Foods Retailed in Osaka Prefecture, Japan

The potential human health risk of Japanese ready-to-eat (RTE) foods was investigated by determining the contamination by foodborne bacterial pathogens, the prevalence of opportunistic and nosocomial pathogens, and the antibiotic susceptibility of the isolates recovered from 96 samples of lightly pickled vegetables, 88 samples of Western-style desserts, and 98 samples of RTE fish and seafood products sold at retail in Osaka, Japan. Staphylococcus aureus, including isolates producing staphylococcal enterotoxin (SE), were isolated from six lightly pickled vegetable products, seven Western-style dessert products, and three RTE fish and seafood products. Of these isolates, one SEC-producing isolate from a cake was identified as community-acquired methicillin-resistant S. aureus, which was multilocus sequence type 8 and staphylococcal cassette chromosome mec type IV. Enterobacteriaceae species, including Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Serratia marcescens, Citrobacter freundii-Citrobacter braakii, and/or the Enterobacter cloacae complex, were isolated from 92 (95.8%) of the lightly pickled vegetable products, 39 (44.3%) of the Western-style dessert products, and 74 (75.5%) of the RTE fish and seafood products. On the basis of the antimicrobial susceptibility profiles of the opportunistic and nosocomial Enterobacteriaceae pathogens, the third-generation cephalosporin, fosfomycin, and quinolone resistance determinants were investigated. We detected AmpC products of the CIT group and a qnrB9 product in 5 and 1 C. freundii-C. braakii isolates, respectively, and fosA gene products in 15 E. cloacae complex isolates. Because RTE foods are consumed without a heating process, the spread of bacterial pathogens from contaminated food to human consumers is possible. RTE foods must be handled using hygienic procedures from the processing steps to the table to reduce the prevalence of potentially pathogenic or pathogenic bacteria and to prevent bacterial growth.

Oral mycobiome in community-dwelling elderly and its relation to oral and general health conditions

OBJECTIVE

Oral fungal infection is generally associated with dysbiosis related to antibiotic use, immunodeficiency, or frailty. However, fungal colonization in a typical population without apparent symptoms and its associated conditions are poorly understood. In this study, oral fungal colonization in community-dwelling and independently living elderly populations was evaluated and factors affecting fungal colonization were analyzed.

SUBJECTS AND METHODS

The subjects (410; 181 males and 229 females) were 75-99 years of age; those under prior antibiotic use were excluded. Fungal populations in the saliva were evaluated by PCR-based molecular techniques. Body mass index (BMI), smoking habits, and oral health conditions were examined.

RESULTS

Salivary fungal amounts exceeded 10⁴  CFU/ml in 63 (15.4%) of 410 subjects. Candida albicans was most frequently detected (98.4%), followed by Candida glabrata (54.0%), and Candida dubliniensis (38.1%) in those subjects with fungi at 10⁴  CFU/ml or over. Fungi at 10⁴  CFU/ml or over in the presence of C. glabrata or C. dubliniensis was significantly associated with low BMI.

CONCLUSIONS

Candida albicans, C. glabrata, and C. dubliniensis dominated the oral mycobiome in Japanese community-dwelling elderly. Lower BMI might signify compromised health status and thus could result in susceptibility to specific candidiasis by C. glabrata and C. dubliniensis.

Community analysis of dental plaque and endotracheal tube biofilms from mechanically ventilated patients

PURPOSE

Mechanically ventilated patients are at risk for developing ventilator-associated pneumonia, and it has been reported that dental plaque provides a reservoir of respiratory pathogens that may aspirate to the lungs and endotracheal tube (ETT) biofilms. For the first time, metataxonomics was used to simultaneously characterize the microbiome of dental plaque, ETTs, and non-directed bronchial lavages (NBLs) in mechanically ventilated patients to determine similarities in respective microbial communities and therefore likely associations.

MATERIAL AND METHODS

Bacterial 16S rRNA gene sequences from 34 samples of dental plaque, NBLs, and ETTs from 12 adult mechanically ventilated patients were analyzed.

RESULTS

No significant differences in the microbial communities of these samples were evident. Detected bacteria were primarily oral species (e.g., Fusobacterium nucleatum, Streptococcus salivarius, Prevotella melaninogenica) with respiratory pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcuspneumoniae, and Haemophilus influenzae) also in high abundance.

CONCLUSION

The high similarity between the microbiomes of dental plaque, NBLs, and ETTs suggests that the oral cavity is indeed an important site involved in microbial aspiration to the lower airway and ETT. As such, maintenance of good oral hygiene is likely to be highly important in limiting aspiration of bacteria in this vulnerable patient group.

Oral Candida isolates and fluconazole susceptibility patterns in older Mexican women

OBJECTIVES

To assess the epidemiologic and microbiologic profile and in vitro fluconazole susceptibility of yeasts isolated from the oral mucosa colonization/infection of elderly patients.

BACKGROUND

It has been reported that in older adults increases the oral colonization by Candida particularly C. non-albicans, showing a decreased response to fluconazole, which increases the risk of recalcitrant local and disseminated candidiasis.

MATERIALS AND METHODS

This was a prospective cross-sectional study conducted in 120 elderly patients. Oral samples were obtained of mucosal Candida colonization or infection by swabbing. Each sample was plated on CHROMagar(®)Candida and incubated (36±1.5°C) for two days. The yeast species were identified using the API(®)ID32-C-AUX. Fluconazole susceptibility was tested using a broth microdilution assay according to the CLSI methods.

RESULTS

The yeast colonization/infection frequency in the total population was 65.8%. The frequency of the highest Candida carriers was 67.4% in the 70-79-year-old-group. Oral candidiasis was present in 20%, with a tendency to increase with age (33.3% of adults aged>80years), it was determined that the use of prosthesis is associated with a higher colonization rate (Chi2, p=0.011). The frequency of colonization/infection cases with more than one species showed a tendency to increase with age; 18.9% in the 60-69 year-old-group, 20.9% in the 70-79-year-old-group and 29.2% in the ≥80 year-old-group. About fluconazole susceptibility: for C. albicans, 20.3%, about Candida non-albicans species 15.3% were dose dependently susceptible (DDS) and 17.9% were resistant.

CONCLUSIONS

After 80 years of age, there is a considerable increase in Candida non-albicans species and a reduced susceptibility to fluconazole.

High prevalence of colonization of oral cavity by respiratory pathogens in frail older patients with oropharyngeal dysphagia

BACKGROUND

Aspiration pneumonia (AP) is caused by dysfunctional swallowing resulting in aspiration of material colonized by respiratory pathogens. The aim of this study was to assess and compare the swallowing physiology, health status, oral health status, and oral/nasal microbiota in frail older patients (FOP) with oropharyngeal dysphagia (OD) and a control group.

METHODS

We studied 47 FOP (>70 year) with OD by videofluoroscopy (17 with acute pneumonia -APN-, 15 with prior pneumonia-PNP- and 15 without) and 14 older controls without OD (H). Oral/nasal colonization by five respiratory pathogens was evaluated by qPCR, whereas commensal microbiota composition was assessed by pyrosequencing.

KEY RESULTS

(i) Frail older patients with OD presented similar comorbidities, poor functionality, polymedication, and prevalent videofluoroscopic signs of impaired safety of swallow (33.3-61.5%). However, patients with OD-APN also presented malnutrition, delayed laryngeal vestibule closure (409.23 ± 115.6 ms; p < 0.05), and silent aspirations (15.6%). (ii) Oral health was poor in all groups, 90% presented periodontitis and 72%, caries. (iii) Total bacterial load was similar in all groups, but higher in the oropharynx (>10(8) CFU/mL) than in the nose (<10(6) CFU/mL) (p < 0.0001). Colonization by respiratory pathogens was very high: 93% in OD patients (p < 0.05 vs H); 93% in OD-PNP (p < 0.05 vs H); 88% in OD-APN (p = 0.07 vs H), and lower in controls (67%).

CONCLUSIONS & INFERENCES

Frail older patients with OD had impaired health status, poor oral health, high oral bacterial load, and prevalence of oral colonization by respiratory pathogens and VFS signs of impaired safety of swallow, and were therefore at risk for contracting AP.

Oral opportunistic infections in institutionalized patients with motor and intellectual disabilities

To establish a basic strategy for prevention of aspiration pneumonia in patients with motor and intellectual disabilities, we investigated oral opportunistic pathogen (OOP) infections in 31 such patients who were resident at a welfare home. Patients received special oral care from a dental hygienist once a week. OOP samples were collected by scraping the dorsal surface of the tongue, and then cultured. For each patient, the basic reasons for admission and the degree of intellectual disability and mobility were recorded. OOPs were found in 61.3% of the patients, of which methicillin-sensitive Staphylococcus aureus (MSSA) was the most commonly detected (38.7%). A significantly high proportion of male patients were OOP-positive, and a significantly high proportion of patients with mental retardation were Candida sp.-positive. However, multivariate logistic regression revealed that disability was not associated with OOP positivity. No correlation was found between OOP positivity and disability. Nevertheless, special oral care may be beneficial for maintenance of oral health in patients with disabilities.

Viability changes: Microbiological analysis of dental casts

Background

This study evaluated the survival of the most prevalent oral bacteria and fungi (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, and Candida albicans) in dental casts, and compared changes in the amounts of these microorganisms at different time intervals to determine how long dental casts may pose threat to the health of dental personnel and patients.

Material/Methods

When manufacturing the casts, regular water was replaced with sterile distilled water, where suspensions of the studied bacteria or the fungus at certain concentrations were prepared. When the dental casts were fully set (solidified), plaster shavings were examined immediately after the contact of the studied microorganism with the plaster, as well as after 1, 2, 24, 48, 72, 96, and 120 hours. Following that, we measured how the amount of the studied bacteria and fungi in 1 gram of the plaster changed within the studied period of time.

Results

Klebsiella pneumoniae survived in plaster for up to 4 days, and the reduction in the number of these bacteria became statistically significant after 1 day (p<0.05). Staphylococcus aureus remained viable in plaster for up to 4 days, and the number of these bacteria dropped after 1 day (p<0.05). Escherichia coli disappeared after 2 days, and a reduction was already observed after 2 hours (p<0.05). Candida albicans in plaster models died within 2 days, and a reduction in their number was observed after 1 day (p<0.05).

Conclusions

The microorganisms did not multiply in the gypsum casts and their number significantly dropped instead of increasing.