Introduction
The anterior nares are the primary reservoirs of Staphylococcus aureus, which is a risk factor for the development of both community-acquired and nosocomial infections.Reference Boelaert, Van Landuyt, de Baere, Deruyter, Daneels and Schurgers1, Reference Kluytmans, Manders, van Bommel and Verbrugh2 The rate of nasal carriage of S aureus strains ranges from 16.8 to 90 per cent;Reference Kluytmans, van Belkum and Verbrugh3–Reference Alghaithy, Bilal, Gedebou and Weily6 thus, its presence may be considered a serious public health problem. Despite antibiotic therapy, staphylococcal infections occur frequently in hospitalised patients, often with severe consequences.Reference Kluytmans, van Belkum and Verbrugh3 Therefore, medical staff, food industry employees, and those working in close contact with people should be periodically assessed regarding S aureus carriage.
In order to fully address this public health problem, it is important to elucidate whether the presence of a moustache affects nasal colonisation of S aureus. Therefore, this study assessed the effect of a moustache on nasal S aureus colonisation through nasal cytology and microbiology testing.
Materials and methods
The study was approved by the local ethics committee of the University of Medipol. Verbal and written informed consent was obtained from all participants. Between March and July 2013, 118 men with a moustache, aged 20–50 years old (study group), and 123 age-matched men without a moustache (control group) took part in the study. The participants in the study group had been wearing a moustache for at least one year, whereas the participants in the control group had shaved the hair in this region daily over the previous year. None of the participants had been hospitalised or treated with antibiotics in the previous three months. Furthermore, none were smokers, and none had any acute upper respiratory tract infection, chronic metabolic disease, immune insufficiency, significant nasal septal deviation or intravenous drug addiction.
Nasal swabs were taken from the right nasal cavity for cytology and from the left nasal cavity for microbiology. The swabbing was performed by anterior rhinoscopy, using a nasal speculum. The swab was soaked in saline before being inserted 1 cm deep into the left nostril and rotated five times. It was then immediately sent to the laboratory for microbiological assessment.Reference Scarnato, Mallaret, Croize, Kouabenan, Dubois and Maitre7 The cells in the right nostril were collected by swabbing the mid part of the inferior turbinate.Reference Meltzer and Jalowayski8 The obtained cells were then dispersed on a slide, allowed to dry and sent for cytological analysis.
Microbiological assessment
The samples were inseminated in 5 per cent sheep blood agar and incubated for 24 hours at 37°C. Gram stain, catalase and coagulase tests were conducted. Positive cocci from the colonies proliferating in the media after 24 hours were identified as S aureus. Development of β-haemolysis was then determined. The Staphylase Test Kit (Oxoid™) was used to establish coagulase efficiency using saline as a negative control. The tube coagulase test was performed on the strains that had a negative coagulase test result and false negativity was excluded. Methicillin resistance was investigated via the Kirby–Bauer disc diffusion method on Muller Hinton agar using a 30 µg cefoxitin disc; isolates with a zone diameter of 21 mm or less were considered to be methicillin-resistant S aureus (MRSA).9
Cytological assessment
The smears were stained using the May–Grünwald–Giemsa stain (Fast Color Kit; DDK Italia, Milan, Italy) and closed with the lamella. The presence of eosinophils, neutrophils and mast cells was assessed under light microscopy, and classified as either existent or non-existent. In addition, a semi-quantitative assessment was performed by scoring no cells as 0, single and multiple cells as 1, and cell-rich clusters as 2.
Statistical evaluation
The Number Cruncher Statistical System (2007) and Power Analysis and Sample Size (2008) statistical software programs (NCSS, Kaysville, Utah, USA) were used for the statistical analyses. The Student's t-test was employed to compare the parameters showing normal distribution, and to provide descriptive statistical data (means, standard deviations, frequencies and ratios). Pearson's chi-square test and Yates' continuity correction test were utilised to compare the qualitative data. Significance was assessed at the level of p < 0.05.
The power analysis indicated that the number of samples required for 80 per cent power, with an α value of 0.05, was 186, when a Δ value of 15 per cent was used for the nasal cytology eosinophil scores. The minimum expected culture growth rate was 45 per cent.
Results
The study comprised 241 participants, 49 per cent (n = 118) of whom had a moustache and 51 per cent (n = 123) did not. The mean ages of the participants in the study group and control group were 33.8 ± 9 years and 34.1 ± 8.4 years, respectively (p > 0.05) (Figure 1).
Age distribution of participants with or without a moustache.
Overall, S aureus bacteria were detected in 19.9 per cent (n = 48) of the participants. The S aureus carrier rates in the study group and control group participants were 19.5 per cent (n = 23) and 20.3 per cent (n = 25), respectively (p > 0.05) (Table I). Among the S aureus carriers, three participants without a moustache and two participants with a moustache had MRSA (p > 0.05).
Microbiology results by group
*Total n = 118; †total n = 123. ‡Pearson's chi-square test. S aureus = Staphylococcus aureus
According to the cytology results, both the study group and control group were similar in terms of the results for neutrophils and mast cells (p > 0.05). However, eosinophil clusters were significantly more prominent in participants with a moustache as compared to those without (Table II). There was no association between the microbiology and cytology results (Table III).
Nasal cytology results by group
*Total n = 118; †total n = 123. ‡Pearson's chi-square test. **p < 0.05
Nasal cytology results according to s aureus carriage
*Total n = 193; †total n = 48. ‡Pearson's chi-square test. **Yates' continuity correction performed. S aureus = Staphylococcus aureus
Discussion
Various studies have assessed S aureus carriage in: medical staff, people involved with food products for human consumption, patients in intensive care units, and individuals with chronic metabolic diseases and intravenous drug dependence. Given the public health implications with regard to nasal S aureus carriage by medical staff, food industry employees and those in close contact with people, some businesses require that employees regularly shave their moustaches and beards, which, for some men, is a social and cosmetic issue. However, whether the presence or absence of a beard or moustache is important in terms of public health remains to be determined.
As a moustache is situated at the entrance to the nostrils, some bacterial contamination might be possible, especially in nasal S aureus carriers. Nevertheless, this study indicated that nasal S aureus carriage is similar in men with and without a moustache. The carrier rate of S aureus observed herein is comparable to those rates reported in the literature.Reference al Bustan, Udo and Chugh10–Reference den Heijer, van Bijnen, Paget, Pringle, Goossens and Bruggeman12 Therefore, having a moustache does not increase the risk of S aureus colonisation in the nose.
When exposed to the causative allergen, either in the environment or during a nasal provocation test, patients suffering from allergic rhinitis develop an immediate nasal response, the so-called early phase response, followed by a late phase response. From a microscopic point of view, these responses are characterised by a mucosal infiltration of inflammatory cells (eosinophils, mast cells and neutrophils).Reference Pelikan and Pelikan-Filipek13, Reference Pelikan and Pelikan-Filipek14 Nasal cytology provides an important contribution to the definition and understanding of the pathophysiological mechanisms of allergic and non-allergic rhinitis.Reference Gelardi, Incorvaia, Passalacqua, Quaranta and Frati15–Reference Gelardi, Maselli del Giudice, Fiorella, Fiorella, Russo and Soleti17 Mast cells and eosinophils are not cells specific to allergic rhinitis. In this study, we comparatively assessed cells that have a role in the pathogenesis of allergic rhinitis in nasal mucosa. The presence of eosinophil clusters was significantly higher in the study group. Furthermore, in general, the numbers of mast and eosinophil cells were higher in this group, although this difference was not statistically significant. However, the groups were not compared in terms of frequency of allergic rhinitis. Thus, this study highlights a new outlook for future related studies investigating the risks of allergic and non-allergic rhinitis in men with a moustache.
• Medical staff, food industry employees and those working in close contact with people should be periodically assessed regarding Staphylococcus aureus carriage
• The presence or absence of a moustache had no effect on nasal S aureus colonisation
• The number of eosinophil clusters was significantly higher in participants with a moustache
In conclusion, the presence or absence of a moustache appears to have no effect on nasal S aureus colonisation. However, further research is required to elucidate whether the presence of a moustache increases the risk of allergic or non-allergic rhinitis.
