Low methicillin-resistant Staphylococcus aureus carriage rate among Italian dental students

Hygiene practices and antibiotic resistance among dental and medical students: a comparative study

PURPOSE

Healthcare students' hand and smartphone hygiene is critical due to potential pathogenic and antibiotic-resistant bacteria transmission. This study evaluates hygiene practices in medical and dental students at Kuwait University, exploring antibiotic resistance gene prevalence.

METHODS

Swab samples were collected from the hands and smartphones of 32 medical and 30 dental students. These samples were cultured on Columbia Blood Agar and McConkey Agar plates to quantify bacterial colony-forming units (CFUs). The extracted DNA from these colonies underwent RT-PCR to identify antibiotic resistance genes, including tem-1, shv, blaZ, and mecA. Additionally, a questionnaire addressing hygiene practices was distributed post-sample collection.

RESULTS

Medical students exhibited more frequent hand hygiene compared to dental students (P ≤ 0.0001). Although significantly fewer bacterial CFUs were found on medical students' smartphones (mean = 35 ± 53) than dental students' (mean = 89 ± 129) (P ≤ 0.05), no significant differences were observed in CFU counts on their hands (medical: mean = 17 ± 37; dental: mean = 96 ± 229). Detection of at least one of the targeted antibiotic resistance genes on medical (89% hands, 52% smartphones) and dental students' (79% hands, 63% smartphones) was not statistically significant. However, the prevalence of two genes, tem-1 and shv, was significantly higher on medical students' hands (78% and 65%, respectively) than on dental students' hands (32% and 28%, respectively).

CONCLUSION

Clinically significant prevalence of antibiotic resistance genes were found on medical and dental students' hands and smartphones, emphasizing the importance of ongoing education regarding hand hygiene and smartphone disinfection. This continuous reinforcement in the curriculum is crucial to minimizing the risk of cross-contamination.

Oral and rectal colonization of methicillin-resistant Staphylococcus aureus in long-term care facility residents and their association with clinical status

Staphylococcus aureus is a commensal bacterium in humans, but it sometimes causes opportunistic infectious diseases such as suppurative skin disease, pneumonia, and enteritis. Therefore, it is important to determine the prevalence of S. aureus and methicillin-resistant S. aureus (MRSA) in individuals, especially older adults. In this study, we investigated the prevalence of S. aureus and MRSA in the oral cavity and feces of residents in long-term care facilities (LTCFs). S. aureus was isolated from the oral cavity of 61/178 (34.3%) participants, including 28 MRSA-positive participants (15.7%), and from the feces of 35/127 (27.6%) participants, including 16 MRSA-positive participants (12.6%). S. aureus and MRSA were isolated from both sites in 19/127 individuals (15.0%) and 10/127 individuals (7.9%), respectively. Among 19 participants with S. aureus isolation from both sites, 17 participants showed the same sequence type (ST) type. Then, we analyzed the correlation of S. aureus and MRSA in the oral cavity and rectum with the participant's condition. S. aureus and MRSA positivity in the oral cavity was significantly related to tube feeding, while there was no correlation of rectal S. aureus/MRSA with any factors. Our findings regarding the oral inhabitation of MRSA and its risk factors indicate the importance of considering countermeasures against MRSA infection in LTCFs.

Genetic Characterization of Staphylococcus aureus, Staphylococcus argenteus, and Coagulase-Negative Staphylococci Colonizing Oral Cavity and Hand of Healthy Adults in Northern Japan

The spread of methicillin resistance and virulence among staphylococci in the community poses a public health concern. In this study, we investigated the prevalence of Staphylococcus species colonizing the oral cavity and hand (skin) of healthy university students and their phenotypic and genetic characteristics in northern Japan. Among a total of 332 subjects, 6 and 110 methicillin-resistant and susceptible Staphylococcus aureus (MRSA and MSSA, respectively) isolates were recovered from 105 subjects. MRSA isolates were genotyped as CC5, CC8, CC45, and CC59 with SCCmec-IIa or IV, among which an isolate of ST6562 (single-locus variant of ST8) harbored SCCmec-IVa, PVL genes and ACME-I, which are the same traits as the USA300 clone. ST1223 S. argenteus was isolated from the oral cavity and hand of a single student. Coagulase-negative Staphylococcus (CoNS) was recovered from 154 subjects (172 isolates), and classified into 17 species, with S. capitis being the most common (38%), followed by S. warneri (24%) and S. epidermidis (15%), including nine mecA-positive isolates. S. capitis was differentiated into seven clusters/subclusters, and genetic factors associated with the NRCS-A clone (nsr, tarJ, ebh) were detected in 10–21% of isolates. The colonization of the USA300-like MRSA variant and S. capitis with the traits of the NRCS-A clone in healthy individuals was noteworthy.

CHX and a Face Shield Cannot Prevent Contamination of Surgical Masks

Background

Bacterial contamination on surgical masks puts a threat to medical staff and patients. The aim of the study was to investigate its contamination during dental treatments, wearing a face shield and performing a pre-procedural mouth rinsing with chlorhexidine (CHX).

Methods

In this prospective, randomized study, 306 treatments were included, 141 single-tooth (restorations) and 165 total dentition treatments (preventive or periodontal supportive ultrasonic application). A total of three groups (each: n = 102) were formed: participants rinsed for 60 s with 0.1 % CHX or with water before treatment, and, for control, a non-rinsing group was included. In view of the COVID-19 pandemic, a face shield covering the surgical mask enhanced personal protective equipment. After treatment, masks were imprinted on agar plates and incubated at 35°C for 48 h. Bacteria were classified by phenotypic characteristics, biochemical assay methods, and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Colonies (CFU) were counted and mean values were compared (Kruskal–Wallis-, U test, p < 0.05).

Results

Chlorhexidine led to a statistically significant reduction of bacterial contamination of the surgical mask (mean: 24 CFU) in comparison with water (mean: 47 CFU) and non-rinsing (mean: 80 CFU). Furthermore, rinsing with water reduced CFU significantly in comparison with the non-rinsing group. There were no significant differences between single or total dentition treatments. Streptococcus spp., Staphylococcus spp., Micrococcus spp., and Bacillus spp. dominated, representing the oral and cutaneous flora.

Conclusion

A pre-procedural mouth rinse is useful to reduce the bacterial load of the surgical mask. However, contamination cannot be prevented completely, even by applying a face shield. In particular, during pandemic, it is important to consider that these additional protective measures are not able to completely avoid the transmission of pathogens bearing aerosols to the facial region. If antiseptic rinsing solutions are not available, rinsing with water is also useful.

Antimicrobial Resistance and Molecular Epidemiological Characteristics of Methicillin-Resistant and Susceptible Staphylococcal Isolates from Oral Cavity of Dental Patients and Staff in Northern Japan

The acquisition of drug resistance and virulence by staphylococcal species colonizing humans is a growing public health concern. The present study was conducted to investigate the prevalence, antimicrobial resistance and genetic characteristics of Staphylococcus isolates from the oral cavity and skin (hand) of systemically healthy subjects with dental disease and dental staff in northern Japan. Among a total of 133 subjects (91 patients and 42 staff), 87 coagulase-positive Staphylococcus (83 S. aureus/4 S. argenteus) and 162 coagulase-negative Staphylococcus (CoNS) isolates were recovered from 59 (44.4%) and 95 (71.4%) subjects, respectively. Three oral isolates were methicillin-resistant S. aureus (MRSA) (3.6%, 3/83) that were genotyped as ST8-SCCmec-IVl, ST4775(CC1)-SCCmec-IVa and ST6562(CC8)-SCCmec-IVa. Remarkably, the ST6562 isolate harbored PVL genes on ΦSa2usa and type I ACME (arginine catabolic mobile element). Four methicillin-susceptible isolates were identified as S. argenteus belonging to ST1223 and ST2250, which harbored enterotoxin genes egc-2 and sey, respectively. Among the fourteen CoNS species identified, methicillin-resistant (MR) isolates were detected in five species (11 isolates, 13.3% of CoNS), with S. saprophyticus and S. haemolyticus being the most common. ACME was prevalent in only S. epidermidis and S. capitis. These findings indicated the potential distribution of USA300 clone-like MRSA, toxigenic S. argenteus and MR-CoNS in the oral cavity of dental patients.

Low prevalence of multi-resistant bacteria in undergraduate dental students; an observational case-control multi-centre study in Europe

Objective: This study assessed the prevalence of MRSA, ESBL and VRE in students from four dental schools in Europe.

Methods: The hand, tongue and nostrils of the students who treated patients (study group) and who did not treat patients (control group) were sampled. After incubation in TSB and subculturing in the presence of 4 µg/ml oxacillin, positive cultures were identified for Staphylococcus aureus by Mannitol salt agar and agglutination tests. The presence of MRSA was confirmed by specific PCR on the species and on the SSCmec genes. ESBL and VRE were isolated using specific CHROMagar and confirmed using antibiotic sensitivity tests.

Results: Of the 879 students who participated in this study (454 students which treated patients, 425 controls) a total of 50 students (5.7%) tested positive for a multi-drug resistant bacterium (MDRB); 13 (1.5%) students tested positive for MRSA, 26 (3.0%) for ESBL and 12 (1.4%) for VRE. No statistically significant differences were found between the students who treated patients compared to the control group for any of the MDRB and study centres, excluding MRSA carriage in the Italian student population. The use of antibiotics the year before sampling, was positively associated with the presence of an MDRB (OR 2.0; 95% Confidence Interval 1.10–3.68; p = 0.02).

Conclusion: The risk for MDRB carriage and sequential transmission of MDRB for dental health care students and their patients were acceptably low.

Colonization of methicillin-resistant Staphylococcus aureus among healthcare students: an integrative review

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a worldwide concern given its presence even in non-hospitalized healthy individuals, such as university students.

OBJECTIVE

To identify in the literature the prevalence of colonization by MRSA among healthcare students.

DESIGN AND SETTING

Integrative review of the literature conducted in Universidade Federal do Piauí.

METHOD

A search for primary studies was performed in the following databases: Medical Literature Analysis and Retrieval System on-line; Cumulative Index to Nursing and Allied Health Literature; Web of Science; Scopus; and LILACS.

RESULTS

This review included 27 studies that demonstrated MRSA infection prevalence ranging from 0.0 to 15.3% among students.

CONCLUSION

The prevalence of colonization of MRSA among healthcare students is high, and the nasal cavity was cited as an important reservoir location for these microorganisms.

Methicillin-Resistant Staphylococcus aureus in the Oral Cavity: Implications for Antibiotic Prophylaxis and Surveillance

The oral cavity harbors a multitude of commensal flora, which may constitute a repository of antibiotic resistance determinants. In the oral cavity, bacteria form biofilms, and this facilitates the acquisition of antibiotic resistance genes through horizontal gene transfer. Recent reports indicate high methicillin-resistant Staphylococcus aureus (MRSA) carriage rates in the oral cavity. Establishment of MRSA in the mouth could be enhanced by the wide usage of antibiotic prophylaxis among at-risk dental procedure candidates. These changes in MRSA epidemiology have important implications for MRSA preventive strategies, clinical practice, as well as the methodological approaches to carriage studies of the organism.

Contamination of surgical mask during aerosol-producing dental treatments

Objectives

Surgical masks are usually contaminated during dental treatment. So far it has not been investigated whether a surgical mask itself can be a source of microbial transmission. The aim of this study was therefore to investigate the microbiological contamination of surgical masks during dental treatment and the transfer of microorganisms from the mask to the hands.

Materials and methods

Five dental treatment modalities were studied: carious cavity preparation (P-caries, n = 10), tooth substance preparation (P-tooth, n = 10), trepanation and root canal treatment (P-endo, n = 10), supragingival ultrasonic application (US-supra, n = 10), and subgingival periodontal ultrasonic instrumentation (US-sub, n = 10). Bacterial contamination of mask and gloves worn during treatment was tested by imprinting on agar plates. Additionally, before masks were tested, their outer surface was touched with a new sterile glove. This glove was also imprinted on agar. Bacteria were identified by MALDI TOF mass spectrometry. Colony-forming units (CFU) were scored: score 0: 0 CFU, score 1: < 10² CFU, score 2: > 10² CFU, score 3: dense microbial growth.

Results

All masks and all gloves used during treatment displayed bacterial contamination (sample scores 0/1/2/3: masks 0/46/3/1 and gloves 0/31/10/9). After touching the masks with new sterile gloves, microorganisms were recovered with the following contamination scores: P-caries: 4/6/0/0, P-tooth: 2/8/0/0: P-endo: 7/3/0/0, US-supra: 0/9/1/0, US-sub: 2/8/0/0. No statistically significant differences were detected between the treatment modalities. Streptococci spp. and Staphylococci spp. representing the oral and cutaneous flora dominated.

Conclusions

Surgical masks are contaminated after aerosol-producing dental treatment procedures. Used masks have a potential to be a source of bacterial contamination of the hands.

Clinical relevance

Dental staff should avoid touching the outer surface of masks with their hands to prevent transmission of pathogens. It is recommendable to change the mask after each treated patient followed by hand disinfection.

Detection of Staphylococcus aureus (MRSA/MSSA) in surfaces of dental medicine equipment

Methicillin-Resistant Staphylococcus aureus (MRSA) represents one of the major causes of nosocomial infections, leading to high mortality. Surfaces in clinics, as well as the attending uniform and the hands of the dental doctor can be MRSA reservoirs. Having this in mind, the purpose of this study was to evaluate the presence of Methicillin-Sensitive Staphylococcus aureus (MSSA) and MRSA on dental medicine equipment surfaces. 354 Samples were collected from six equipment surfaces in six attendance areas before and after patient consultation and cultured in a selective medium. Polymerase Chain Reaction (PCR) was used to confirm the identity of bacterial strains as MRSA or MSSA. Data analysis was performed with chi-square tests with Bonferroni correction. It was observed 55.6% of uncontaminated samples. Contamination was: 17.5% MRSA (5.9% of samples collected before patient attendance and 11.6% after); 39.3% MSSA (14.1% collected before and 25.2% after). The prevalence of MRSA and MSSA was significantly higher after patient care. Integrated Clinic represented the most contaminated attendance area (MRSA − 41.7%, MSSA − 51.2%), the chair arm rest was the most contaminated surface for MRSA (29.7%) and the dental spittoon the most contaminated surface for MSSA (23.5%). Although a low level of contamination was observed, dental clinics, through patients possibly carrying bacteria, may be reservoirs for MRSA and MSSA transmission, and might contribute to potential nosocomial infections.

School environmental contamination of methicillin-sensitive Staphylococcus aureus as an independent risk factor for nasal colonization in schoolchildren: An observational, cross-sectional study

Objective

We aim to assess the similarities of proportional, phenotypic, and molecular characteristics between the school environment and schoolchildren on methicillin-sensitive S. aureus (MSSA) isolates.

Methods

A cross-sectional study was conducted between March 2016 and August 2016 in eight elementary schools in Guangzhou, China. Nasal swabs from students and environmental swabs from school environments were collected. Univariate and multivariate logistic regression analyses under a multistage stratified cluster cross-sectional survey design were performed to access the prevalence relationship and influencing factors, respectively. Phenotypic and molecular characterizations of MSSA isolates were conducted using the Kirby-Bauer disk diffusion method and polymerase chain reaction assays, respectively.

Results

In total, 1705 schoolchildren and 1240 environmental samples from 40 classes in eight elementary schools obtained between March and August 2016 were include in this study. The rates of MSSA prevalence among schoolchildren and the environment were 11.44% (195/1705) and 4.60% (57/1240), respectively. The odds ratios and 95% confidence intervals (CIs) on the prevalence of MSSA isolates were 1.11 (95% CI, 1.05–1.29; P = 0.010) and 1.04 (95% CI, 1.01–1.07; P = 0.003) for the school or class environment and students, respectively. Similar phenotypic and molecular characteristics were identified between schoolchildren and the environment. A cause and effect relationship could not be established because the study design was cross-sectional.

Conclusions

Because of the cross-sectional design, we can reveal the association between school environment and schoolchildren on MSSA, but it is not a cause and effect relationship.

Cross-transmission in the Dental Office: Does This Make You Ill?

PURPOSE OF REVIEW

Recently, numerous scientific publications were published which shed new light on the possible risks of infection for dental healthcare workers and their patients. This review aimed to provide the latest insights in the relative risks of transmission of (pathogenic) micro-organisms in the dental office.

RECENT FINDINGS

Of all different routes of micro-organism transmission during or immediately after dental treatment (via direct contact/via blood-blood contact/via dental unit water and aerosols), evidence of transmission is available. However, the recent results put the risks in perspective; infections related to the dental office are most likely when infection control measures are not followed meticulously.

SUMMARY

The risk for transmission of pathogens in a dental office resulting in an infectious disease is still unknown; it seems to be limited in developed countries but it cannot be considered negligible. Therefore, maintaining high standards of infection preventive measures is of high importance for dental healthcare workers to avoid infectious diseases due to cross-contamination.

Knowledge, attitudes and practices regarding methicillin-resistant Staphylococcus aureus (MRSA) infection control and nasal MRSA carriage rate among dental health-care professionals

BACKGROUND

Dental health-care professionals (DHCPs) with nasal colonisation of methicillin-resistant Staphylococcus aureus (MRSA) can serve as a reservoir for MRSA transmission to others and be exposed to self-contamination with MRSA. Evaluating the knowledge, attitudes and actual practice of DHCPs is imperative for appropriate infection control.

METHODS

Dentists, dental hygienists and dental technologists from Seoul National University Dental Hospital were recruited to participate in a cross-sectional survey and undergo nasal sampling of MRSA. The survey included demographic questions, six questions about knowledge, eight questions about attitudes/perceptions and six questions about practices/behaviours regarding MRSA infection control. Nasal samples from the participants were analysed for MRSA presence, antimicrobial susceptibility and staphylococcal cassette chromosome mec (SCCmec) typing. MRSA carriers underwent decolonisation with topical mupirocin.

RESULTS

Among 139 DHCPs, four (2.9%) were nasal MRSA carriers. Decolonisation was successful in three participants. One participant was decolonised with topical fusidic acid after failure to decolonise with mupirocin. Dentists had a higher knowledge score compared with the other professionals (P < 0.05). Dental hygienists scored higher on practice questions compared with the other professionals (P < 0.05). There was a significant, positive correlation between attitude and practice scores (P < 0.01).

CONCLUSIONS

The nasal MRSA carriage rate among DHCPs is 2.9%, which is higher than that in the general population but lower than that in other health-care professionals. Further education of DHCPs on MRSA, especially regarding its seriousness, is needed to improve MRSA infection control in a dental hospital setting.