Staphylococcus aureus in the oral cavity: a three-year retrospective analysis of clinical laboratory data

OBJECTIVE: A retrospective analysis of laboratory data to investigate the isolation of Staphylococcus aureus from the oral cavity and facial area in specimens submitted to a regional diagnostic oral microbiology laboratory. METHODS: A hand search of laboratory records for a three-year period (1998-2000) was performed for specimens submitted to the regional diagnostic oral microbiology laboratory based at Glasgow Dental Hospital and School. Data were collected from forms where S. aureus was isolated. These data included demographics, referral source, specimen type, methicillin susceptibility and clinical details. RESULTS: For the period 1998-2000, there were 5,005 specimens submitted to the laboratory. S. aureus was isolated from 1,017 specimens, of which 967 (95%) were sensitive to methicillin (MSSA) and 50 (5%) were resistant to methicillin (MRSA). The 1,017 specimens were provided from 615 patients. MRSA was isolated from 37 (6%) of patients. There was an increasing incidence of S. aureus with age, particularly in the >70 years age group. The most common specimen from which MSSA was isolated was an oral rinse (38%) whilst for MRSA isolates this was a tongue swab (28%). The clinical condition most commonly reported for MSSA isolates was angular cheilitis (22%). Erythema, swelling, pain or burning of the oral mucosa was the clinical condition most commonly reported for MRSA isolates (16%). Patients from whom the MSSA isolates were recovered were most commonly (55%) seen in the oral medicine clinic at the dental hospital, whilst patients with MRSA were more commonly seen in primary care settings such as nursing homes, hospices and general dental practice (51%). CONCLUSION: In line with more recent surveys, this retrospective study suggests that S. aureus may be a more frequent isolate from the oral cavity than hitherto suspected. A small proportion of the S. aureus isolates were MRSA. There were insufficient data available to determine whether the S. aureus isolates were colonising or infecting the oral cavity. However, the role of S. aureus in several diseases of the oral mucosa merits further investigation.     

Staphylococcus aureus transmission through oronasal fistula in children with cleft lip and palate

Objective: To determine the presence of Staphylococcus aureus in a nasal flora and oral environment, the correlation between frequency of transmission of S. aureus and oronasal fistula size, and the pattern of methicillin resistance on S. aureus strains in children with cleft lip and palate (CLP). Design: Thirty-two CLP children with and without oronasal fistulas, ranging in age from 5 to 13 years were examined for oronasal fistula presence and size. Stimulated saliva samples and nasal swab samples were taken and investigated for S. aureus presence. S. aureus presence and counts were correlated with fistula presence and size. Results: Saliva samples showed statistical differences between the groups with and without oronasal fistulas with an area ranging from 0.80 to 28.26 mm(2). The S. aureus counts were significantly higher (r = .535, p = .002) in saliva samples from children with larger oronasal fistula. The S. aureus count was not significantly different (r = -.013, p = .942) in nasal samples compared with oronasal fistula size. Methicillin resistance with disk-diffusion method was recorded as sensitive (>/=13 mm) in all S. aureus strains. Conclusions: The results of this study indicate a positive correlation between fistula size and S. aureus transmission to one oral environment through oronasal fistulae, and a positive correlation between frequency of S. aureus transmission and fistula size. All S. aureus strains were sensitive to methicillin. These results may have implications for preventive treatment of CLP children.     

Staphylococcus aureus and other bacteria in untreated periodontitis

Whether the subgingival microbiota differ between individuals with chronic and those with aggressive periodontitis, and whether smoking influences bacterial composition, is controversial. We hypothesized that the subgingival microbiota do not differ between sites in individuals with chronic or aggressive periodontitis, or by smoking status. Bacterial counts and proportional distributions were assessed in 84 individuals with chronic periodontitis and 22 with aggressive periodontitis. No differences in probing pocket depth by periodontal status were found (mean, 0.11 mm; 95% CI, 0.6 to 0.8, p = 0.74). Including Staphylococcus aureus, Parvimonas micra, and Prevotella intermedia, 7/40 species were found at higher levels in those with aggressive periodontitis (p < 0.001). Smokers had higher counts of Tannerella forsythia (p < 0.01). The prevalence of S. aureus in non-smokers with aggressive periodontitis was 60.5%. The null hypothesis was rejected, in that P. intermedia, S. aureus, and S. mutans were robust in diagnosing sites in individuals with aggressive periodontitis. S. aureus, S. sanguinis, and T. forsythia differentiated smoking status.     

The effects of professional oral health care on patients in the subacute stage of emergent neurosurgical disorders

This study evaluated the effectiveness of professional oral health care (POHC) on patients who were in the subacute stage of neurosurgical disorders. Forty subjects (26 male, 14 female) with acute cerebrovascular disorders or neurotrauma were randomly divided into two groups. The intervention group (n = 21) received POHC treatment by dental hygienists, and the control group (n = 19) did not. To evaluate the change in oral health status of the subjects, an oral examination was carried out at baseline and four weeks later. For the subjects in the intervention group, periodontal condition, oral hygiene status, and oral function improved statistically significantly. The detection rate for methicillin‐resistant Staphylococcus aureus (MRSA) was statistically significantly lower in the intervention group than in the control group. These results suggest that POHC performed by dental hygienists in collaboration with nurses plays an important role in the promotion not only of oral health but also of general health.     

Methicillin‐resistant staphylococci carriage in the oral cavity: a study conducted in Bari (Italy)

Oral Diseases (2010) 16 , 465–468 Objectives: The oral cavity may represent a site of colonization by antibiotic‐resistant bacteria, such as methicillin‐resistant staphylococci (MRS). To define the prevalence of staphylococci and MRS in the oral cavity, an observational study was carried out in the city of Bari (Italy). Methods: Sixty subjects were asked to provide oral samples and a questionnaire about risk factors of colonization by MRS. An enrichment medium specific for staphylococci was used for the isolation. Results: Swabs and corresponding questionnaires were available from 36 out of 60 patients. Staphylococci were isolated from seven out of 36 samples (prevalence 19.4%). Among the seven staphylococcal isolates, three were Staphylococcus aureus, and one strain, belonging to S. epidermidis species, was found to be MR (1.7%). No methicillin‐resistant S. aureus were isolated. Five out of seven staphylococcal isolates exhibited resistance to more than two classes of non‐beta‐lactams antimicrobials. None of the risk factors analysed correlated with the status of MRS carriers, except the presence of oral disease. Conclusions: The results underline the potential role of the oral cavity as a reservoir of staphylococci.     

Factors affecting susceptibility of Staphylococcus aureus to antibacterial agents

Staphylococcus aureus is a major human pathogen that causes suppurative diseases, toxic shock syndrome, pneumonia, food poisoning, and staphylococcal scalded skin syndrome (SSSS). S. aureus can also cause osteomyelitis and radicular cysts that impact dental health. β-lactam antibiotics are frequently used for the treatment of S. aureus infections, but the emergence of methicillin-resistant S. aureus (MRSA) has caused serious problems for the antibiotic treatment of S. aureus infections. PBP2′ has a low affinity for methicillin antibiotics and is one of the factors responsible for resistance to these antibiotics. However, clinical MRSA isolates show various levels of resistance to methicillin that are not determined by the amount of PBP2′, indicating that other factors are also involved. Furthermore, while vancomycin is very effective against MRSA, vancomycin-resistant and vancomycin-intermediate S. aureus have recently been reported. Many studies have been undertaken to better understand methicillin and vancomycin resistance mechanisms through identification of the factors affecting susceptibility to β-lactams. We recently demonstrated that MRSA showed resistance to antimicrobial peptides produced by humans that are a component of the innate immune system, in addition to various antibiotics.     

Influence of oral conditions on colonization by highly toxigenic Staphylococcus aureus strains

Oral Diseases (2012) 18 , 402–409 Objectives: As the oral cavity is regarded as a relevant site for Staphylococcus aureus colonization and interhuman transmission, this study aimed to investigate whether different oral conditions influence the rates of S. aureus oral carriage and genetic characters of S. aureus isolates. Subjects and methods: Staphylococcus aureus was searched in samples collected from cheek, gingival margin, and anterior nares of 45 healthy subjects, 27 periodontitis affected subjects, and 29 subjects with fixed prosthetic restorations. Isolates were screened for 17 genetic determinants, and Partial Least Square Discriminant Analysis was performed to evaluate whether specific characters correlated with oral condition or site of isolation. Results: The three subject groups showed comparable nasal carriage rates but, both the periodontitis and prosthetic restoration groups showed significantly higher oral carriage rates, as compared to healthy subjects (P = 0.01 and 0.02, respectively). Moreover, periodontitis affected subjects hosted strains possessing a distinct genotypic and phenotypic background, characterized by the presence of a larger number of exotoxins encoding genes. Conclusions: These data confirm that the oral cavity is an important site of S. aureus colonization and demonstrate that conditions modifying the oral environment, as the presence of periodontitis and of fixed prosthetic restorations, promote S. aureus carriage and may favor the spread of more pathogenic strains.     

Staphylococcus lugdunensis--a potential pathogen in oral infection.

OBJECTIVE: The purpose of this study was to investigate the pathogenicity of Staphylococcus lugdunensis in acute oral infection. STUDY DESIGN: S. lugdunensis was isolated from patients with acute oral infections and from healthy control subjects. Antibiotic susceptibility, in vitro cellular toxicity, in vivo virulence, and hemolytic activity testing and dot blot analysis were performed. The statistical significance of in vitro cellular toxicity was determined by means of analysis of variance. RESULTS: Isolated from the infected patients, S. lugdunensis showed resistance to penicillin, ampicillin, methicillin, cephalothin, and clindamycin, exhibited virulence in vivo, and showed delta-like hemolysin activity. Four of the 6 strains of S. lugdunensis gave synergistic hemolysis. In dot blot analysis, S. lugdunensis showed a positive reaction to the probe of the delta-hemolysin gene in S. aureus. CONCLUSIONS: The results suggest that S. lugdunensis may be a potential pathogen in acute oral infection.     

Two cases of oral infection by methicillin-resistant Staphylococcus aureus

Two cases of oral infection with multi-resistant Staphylococcus aureus (MRSA) are described who were found to carry the same MRSA. Both cases were managed without the use of antibiotics. The practitioner was found not to have worn gloves routinely and this may have been the source of the MRSA.     

Oral staphylococcal mucositis: A new clinical entity in orofacial granulomatosis and Crohn's disease

OBJECTIVE: Orofacial granulomatosis and the oral manifestations of Crohn's disease comprise many clinical features, of which stomatitis is one. The purpose of this study was to establish a role for Staphylococcus aureus in mucositis affecting some patients with orofacial granulomatosis or oral Crohn's disease. STUDY DESIGN: Four patients (2 with orofacial granulomatosis and 2 with oral Crohn's disease), from a total of 450 patients examined over 10 years, had stomatitis involving the entire oral mucosa, from which S aureus was cultured by the oral rinse technique. These patients were treated with flucloxacillin or erythromycin. RESULTS: A heavy growth of S aureus was isolated from the mouth of each patient. All 4 patients responded to treatment with flucloxacillin or erythromycin. CONCLUSIONS: S aureus is a potential cause of panstomatitis in patients with orofacial granulomatosis or Crohn's disease. This infection responds rapidly to antimicrobial treatment.     

Relationship between oral motor dysfunction and oral bacteria in bedridden elderly

OBJECTIVE: The purpose of this study was to analyze the relationship between oral bacterial colonization and oral motor dysfunction. STUDY DESIGN: Oral motor dysfunction (swallowing and speech disorders) and detection of oral bacterial species from dental plaque in 55 elderly persons who had remained hospitalized for more than 3 months were investigated and statistically analyzed. RESULTS: The detection rates of methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Streptococcus agalactiae, and Stenotrophomonas maltophilia were significantly higher in subjects with than in those without a swallowing disorder. A similar result was found with regard to the presence of a speech disorder. About half of subjects who had oral motor dysfunction and hypoalbuminemia had colonization by MRSA and/or Pseudomonas aeruginosa. CONCLUSION: These results suggest that the combination of oral motor dysfunction and hypoalbminemia elevated the risk of opportunistic microorganisms colonization in the oral cavity of elderly patients hospitalized over the long term.     

Correlations between bacterial levels in autologous subgingival plaque and saliva of adult Sudanese

The aim of this study was to assess levels of oral bacteria and their correlations in paired samples of saliva and subgingival plaque in a population of adult Sudanese. Whole saliva and pooled subgingival plaque samples from six probing sites of one tooth in each jaw were obtained from 56 Sudanese adults (mean age 35.2+/-8.9 years). Levels of 24 oral bacteria in the autologous saliva and pooled plaque sample of each subject were assessed by DNA probes and checkerboard DNA-DNA hybridization. There were significantly ( P< or =0.01) higher percentages of subjects with > or =10(5) bacterial cells of Prevotella intermedia, Campylobacter rectus, Veillonella parvula, Streptococcus mutans, Lactobacillus acidophilus, Streptococcus anginosus, Streptococcus salivarius, and Leptotrichia buccalis and significantly ( P< or =0.01) lower percentages with Treponema denticola in saliva than in subgingival plaque. The detection frequencies at > or =10(6) bacterial cells were significantly higher for Selenomonas sputigena, S. anginosus, Streptococcus sanguis, and S. salivarius and significantly lower for Porphyromonas gingivalis in saliva than in subgingival plaque ( P< or =0.01). Porphyromonas gingivalis, Fusobacterium nucleatum, S. sputigena, S. sanguis, and Streptococcus mitis demonstrated significant ( P< or =0.05) positive correlations between their levels in plaque and saliva. This study indicates that the levels of P. gingivalis, F. nucleatum, S. sputigena, S. sanguis, and S. mitis correlate significantly in saliva and subgingival plaque and that higher accuracy of detection and assessment of the levels of these bacteria in the oral cavity may be achieved by concurrent sampling of saliva and subgingival plaque.     

Risk Factors for Methicillin-Resistant Staphylococcus aureus (MRSA) and Use of a Nasal Mupirocin Ointment in Oral Cancer Inpatients.

PURPOSE: Elimination of methicillin-resistant Staphylococcus aureus (MRSA) is of critical importance in oral and maxillofacial surgery because control is very difficult once infection of an oral tumor or oral wound with MRSA is established. PATIENTS AND METHODS: We retrospectively investigated the risk factors for acquiring MRSA in 518 patients with oral cancer among 1,877 inpatients in our department between 1984 and 2005. RESULTS: The patients with oral cancer demonstrated a high rate of MRSA colonization and infection (77.8%) relative to the population as a whole with MRSA isolated percentage in our department after 1991. The risk factors for MRSA in oral cancer patients are also related to systemic diseases and physiological and iatrogenic conditions, including cerebrovascular diseases (77.8%), peripheral arterial catheterization (69.2%), diabetes (50.0%), tracheotomy (50.0%), renal failure (50.0%), long-term broad-spectrum antibiotic use (45.7%), and malnutrition (43.3%). However, the highest risk of MRSA seems to be related to poor hygienic care. CONCLUSIONS: Beginning in 1999, we implemented a strategy for reducing infection by MRSA that included nasal mupirocin ointment for patients at high risk of MRSA; since then, the detection rate has decreased. We suggest that the administration of nasal mupirocin ointment and provision of scrupulous hygienic care for high-risk patients are useful and effective measures for decreasing the incidence of MRSA infection.     

Oral health promotion interventions on oral reservoirs of staphylococcus aureus: a systematic review

The oral cavity serves as a reservoir of Staphylococcus aureus for infection of the lower respiratory tract and cross-infection to other patients. This systematic review was designed to examine the effectiveness of oral health promotion interventions on this pathogen. The PubMed, ISI Web of Science, and Cochrane Library databases were searched for clinical trials assessing the effect of oral health promotion interventions on oral and oropharyngeal carriage of S. aureus. Oral health promotion interventions on oral reservoirs of S. aureus in both systemically healthy and medically compromised groups consisted of oral hygiene interventions only. There was a lack of evidence pertaining to the effectiveness of mechanical oral hygiene interventions against this pathogen. Chlorhexidine delivered in oral hygiene products such as mouthrinses, gels, and sprays appeared to have some utility against S. aureus, although some studies found equivocal effects. There was a dearth of studies investigating the efficacy of other chemical agents. Although many chemical agents contained in oral hygiene products have proven in vitro activity against S. aureus, their clinical effectiveness and potential role as adjuncts or alternative therapies to conventional treatment remain to be confirmed by further high-quality randomized controlled trials.     

Isolation and characterization of subgingival staphylococci from periodontitis patients and controls

OBJECTIVES: To isolate and characterize subgingival staphylococci from patients with periodontal disease and from periodontally healthy controls, to evaluate the periodontal environment as a potential source for systemic staphylococcal infections. METHODS: Periopaper strips were used to isolate subgingival staphylococci from 28 patients with chronic periodontitis and 28 periodontally healthy age and sex-matched controls. Staphylococci were identified by microbiological methods and antibiotic resistance profiles determined. RESULTS: Staphylococci were isolated from 54% diseased subgingival and 43% healthy subgingival sites in over 50% periodontitis patients and from 29% healthy subgingival sites in 54% controls. No significant differences in the frequency of isolation or numbers of staphylococci isolated from diseased and healthy sites were noted. Staphylococcus epidermidis was the predominant oral species. Seventy per cent (115 of 165) of all isolates were penicillin-resistant. CONCLUSIONS: Subgingival staphylococci are present in both periodontitis patients and controls. In periodontitis there is an increased risk of bacteraemia because of the increased dentogingival surface area. The dental and periodontal health of patients at risk from haematogenous infections should therefore be maintained at a high level. Antibiotic resistance profiles of the oral staphylococcal isolates suggest that amoxicillin may no longer be a suitable antibiotic for prophylaxis against systemic infections such as prosthetic valve endocarditis.     

One-year bacterial colonization patterns of Staphylococcus aureus and other bacteria at implants and adjacent teeth

AIMS: (i) To assess the pattern of early bacterial colonization on titanium oral implants after installation, at 12 weeks and at 12 months, (ii) to compare the microbiota at submucosal implant sites and adjacent subgingival tooth sites and (iii) to assess whether or not early colonization was predictive of 12-month colonization patterns. MATERIAL AND METHODS: Submucosal/subgingival plaque samples from 17 titanium oral implants and adjacent teeth were analyzed by checkerboard DNA-DNA hybridization 30 min, 12 weeks and 12 months after implant installation. RESULTS: At 12 months, none of the inserted implants had been lost or presented with signs of peri-implantitis. The distribution of sites at implants and teeth with bleeding on probing varied between 2% and 11%. Probing pocket depths < or =3 mm were found at 75% of implant sites. At 12 months, the sum of the bacterial counts of 40 species was statistically significantly higher at tooth compared with implant sites (mean difference: 34.4 x 10(5), 95% confidence interval -0.4 to 69.4, P<0.05). At 12 months, higher individual bacterial counts at tooth sites were found for 7/40 species compared with implant sites. Detection or lack of detection of Staphylococcus aureus at implant sites at 12 weeks resulted in the highest positive (e.g. 80%) and negative (e.g. 90%) predictive values, respectively. Between 12 weeks and 12 months, the prevalence of Tannerella forsythia increased statistically significantly at implant sites (P<0.05). Lack of detection of Porphyromonas gingivalis at 12 weeks yielded a negative predictive value of 93.1% of this microorganism being undetectable at implant sites at 12 months. CONCLUSIONS: Within the limits of this study, the findings showed (i) a few differences in the prevalence of bacterial species between implant and adjacent tooth sites at 12 months and (ii) high positive and negative predictive values for selected bacterial species.     

Infection of surgical wounds in the maxillofacial region and free flap donor sites with methicillin-resistant Staphylococcus aureus

We studied the acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in two groups of patients who had free flap reconstructions of defects after excision of lesions in the head and neck. The first group (n=31) was given a 5-day perioperative course of antibiotic prophylaxis (long-term) and the second (n=33) a 24-h course (short-term). MRSA was the main infecting organism. Seventeen of the 64 patients (27%) developed an infection with MRSA, including seven at donor sites of free flaps. All infections were acquired after operation, and delayed healing or discharge in five patients with MRSA and four with infections with other organisms. The median length of hospital admission was greater for patients that acquired MRSA (p=0.005). There were significantly fewer patients with wounds infected by MRSA in the short-term group (4/33 compared with 13/31, p=0.01). We recommend the short-term use of an antibiotic for surgical prophylaxis and the application of cross-infection control measures on the ward.     

Prevalence of oral methicillin-resistant Staphy/ococcus aureus in an institutionalized veterans population

Methicillin-resistant Staphylococcus aureus ( MRSA) is a nosocomial pathogen now of great concern in nursing homes and other institutional settings. MRSA has been well-documented to inhabit the nares, skin wounds, and respiratory tract, but little is known about its presence in the oral cavity. In this study, all patients admitted to an 80-bed VA extended care facility were cultured weekly for 12 weeks to detect the presence of MRSA in the nares, wounds, in-dwelling devices, and the oral cavity. Of a total of 107 participating subjects, 20 cultured positive for oral MRSA, yielding a prevalence of 18.7%, compared with 19.6% prevalence in the nares —the traditionally accepted screening site for MRSA. There was a 91.6% agreement between oral and nasal carriage in subjects, but four of 107 subjects (3.7%) cultured positive for oral MRSA without evidence of nasal carriage. These results suggest that oral MRSA may be more common than previously thought in high-risk settings, with a prevalence comparable with that of nasal infection. Further investigation is necessary to characterize the factors associated with the presence of MRSA in the oral cavity     

腮腺唾液富组蛋白抗菌活性的研究

为探讨富组蛋白（ｈｉｓｔｉｄｉｎｅｒｉｃｈｐｏｌｙｐｅｐｔｉｄｅｓ，ＨＲＰｓ）的抗菌作用，进一步阐明唾液的正常生理功能，我们采用二种微量且敏感的琼脂糖弥散抗菌实验，分析了腮腺唾液中ＨＲＰｓ的抗菌活性。研究结果不但证实ＨＲＰｓ对变形链球菌ＭＴ６Ｒ株确有抗菌活性，还首次发现ＨＲＰｓ对金黄色葡萄球菌ＡＴＣＣ２５９２３株、大肠杆菌ＭＬ３５Ｐ株及绿脓杆菌ＡＴＣＣ２７８５３株也有很强的抗菌活性。观察表明，在腮腺唾液中起抗菌作用的主要是ＨＲＰ３、ＨＲＰ５和ＨＲＰ６。ＨＲＰｓ对血链球菌Ｓ３４Ｓｒ株无抗菌活性。该项研究结果表明，ＨＲＰｓ实际上为一组内源性广谱抗生素肽，对霉菌、革兰氏阳性与阴性细菌均有抗菌作用。ＨＲＰｓ除具有防龋功能外，还可能是口腔中对抗多种微生物感染的重要分子，应该进行深入研究。     

Antibiotic resistance and production of inhibitory substances among bacterial strains isolated from the oral cavities of BALB/c mice

In the oral cavities of BALB/c mice, microbial population levels are regulated by multifactorial processes. Factors include the production of inhibitory substances and the exchange of genetic material. In this work, 371 isolates from different sites (saliva, tongue, teeth, and mucosa) of the oral cavities of BALB/c mice were screened for resistance to antibiotics and antimicrobial activity. Antibiotic-resistant strains represented 25% of the total flora. Among the predominant species, all the S. faecalis isolates showed multiresistance, and 23% of the Lactobacillus murinus isolates and 15% of the Staphylococcus aureus were resistant to at least one antibiotic. Resistance to aminoglycosides (neomycin, streptomycin, kanamycin, and gentamicin) was most frequently encountered. In S. faecalis, high levels of resistance were recorded to neomycin and streptomycin but not to gentamicin or kanamycin. Macrolides (M), lincosamides (L), streptogramin B (S), tetracycline (Tc), and chloramphenicol (Cm) resistance was also present in multiresistance patterns, especially among S. faecalis isolates. Hemolytic (Hly+) streptococci were less resistant to MLS, Tc, and Cm than were non-hemolytic (Hly-) isolates. Resistance to beta-lactam antibiotics was detected only among staphylococci and with a low prevalence (4%). The frequencies of strains producing antimicrobial substances against the indicator strains (S. mutans LG-1, S. sanguis Ny 101, and A. viscosus Ny 1) were high for L. murinus (76%) and S. faecalis (57% for Hly- and 90% for Hly+), but low for S. aureus (7%). These results indicate that the indigenous oral flora could interfere with colonization by allochthonous micro-organisms and that resistance patterns should be taken into account for the elimination of the oral indigenous flora by antibiotic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)