Prevalence of biofilm and betalactamase-producing staphylococcus in nasal and throat isolates from healthy volunteers: a medical alert

Objective: To study the prevalence of virulence factors such as Biofilm and Beta-lactamase in Staphylococcus isolates residing in nasal and throat mucosa in healthy volunteers

Materials and Methods: Nasal and throat swabs were taken from 100 healthy volunteers at Gulf Medical University and Gulf Medical College Hospital, Ajman, UAE, and cultured for Staphylococcus isolates on appropriate culture media. The isolate were classified as Staphylococcus aureus or Coagulase Negative Staphylococcus [CoNS] based on the growth characteristics on Mannitol Salt Agar and standard tube coagulase test. They were further tested for Biofilm production by Christensen's tissue culture plate and Congo red agar methods. The positive samples were identified for beta-lactamase by iodometric tube method

Results: Of the 100 Staphylococcus isolates, 41 were Staphylococcus aureus of which 25 [61%] were positive for biofilm production whereas 19 [46.3%] were Beta-lactamase positive. Of the 16 [39%] biofilm negative Staphylococcus aureus isolates, 13 [31.7%] were Beta-lactamase positive. Among the 59 CoNS isolates, 38 [64.4%] were positive for biofilm production and 18[30.5%] were Beta-lactamase positive

Twenty one CoNS samples [35.5%] were negative for both biofilm and Beta-lactamase production. Biofilm production in Staphylococcus aureus and CoNS did not show any significant difference [61% and 64.4%]. Predominance of Staphylococcal isolation was in males between the age group of <20 years, mostly from the nasal site

Conclusion: Biofilm-producing Staphylococcus appear to inhabit the normal flora of the nasal and throat mucosa of healthy individuals. Beta-lactamase production was found to be higher in Staphylococcus aureus positive for biofilm producers as compared to CoNS. Transmission of these biofilm producers with drug resistance factors from the healthy individuals to those at risk, like patients on long term catheterization or with indwelling devices need to be considered

Prevalence of biofilm and betalactamase-producing staphylococcus in nasal and throat isolates from healthy volunteers: a medical alert

To study the prevalence of virulence factors such as Biofilm and Beta-lactamase in Staphylococcus isolates residing in nasal and throat mucosa in healthy volunteers. Nasal and throat swabs were taken from 100 healthy volunteers at Gulf Medical University and Gulf Medical College Hospital, Ajman, UAE, and cultured for Staphylococcus isolates on appropriate culture media. The isolate were classified as Staphylococcus aureus or Coagulase Negative Staphylococcus [CoNS] based on the growth characteristics on Mannitol Salt Agar and standard tube coagulase test. They were further tested for Biofilm production by Christensen's tissue culture plate and Congo red agar methods. The positive samples were identified for beta-lactamase by iodometric tube method. Of the 100 Staphylococcus isolates, 41 were Staphylococcus aureus of which 25 [61%] were positive for biofilm production whereas 19 [46.3%] were Beta-lactamase positive. Of the 16 [39%] biofilm negative Staphylococcus aureus isolates, 13 [31.7%] were Beta-lactamase positive. Among the 59 CoNS isolates, 38 [64.4%] were positive for biofilm production and 18[30.5%] were Beta-lactamase positive. Twenty one CoNS samples [35.5%] were negative for both biofilm and Beta-lactamase production. Biofilm production in Staphylococcus aureus and CoNS did not show any significant difference [61% and 64.4%]. Predominance of Staphylococcal isolation was in males between the age group of <20 years, mostly from the nasal site. Biofilm-producing Staphylococcus appear to inhabit the normal flora of the nasal and throat mucosa of healthy individuals. Beta-lactamase production was found to be higher in Staphylococcus aureus positive for biofilm producers as compared to CoNS. Transmission of these biofilm producers with drug resistance factors from the healthy individuals to those at risk, like patients on long term catheterization or with indwelling devices need to be considered

Staphylococcus aureus: prevalence among normal healthy individuals

To determine the prevalence of Staphylococcus aureus among normal healthy individuals in relation to age, gender and site of isolation. This cross sectional study was carried out among normal healthy individuals in the age group 15-65 years, at Gulf Medical University and Gulf Medical College Hospital and Research Center, Ajman. The study included a detailed proforma of all the volunteers. The nasal and throat swabs were collected with strict aseptic precautions and were subjected to direct microscopic examination and culture on appropriate media. Staphylococcal isolates were subjected for Tube Coagulase test and growth on Mannitol Salt Agar [MSA] and were grouped as Staphylococcus aureus and Coagulase Negative Staphylococci [CoNS]. Of the 127 human volunteers screened, 67 were from GMU [22 were staff and 45 M.B.B.S students] and 60 volunteers from GMCH and RC, Ajman [doctors, staff nurses and ward boys]. Staph, aureus isolation was the highest among the 21-30 year age group [37%] with male predominance [59.6%] and mostly from the nasal swabs [56.45%]. The yield of Staph. aureus isolates from the nasal mucosa and throat were only from 49 normal individuals, hence the prevalence of Staph. aureus in our study being 38.5%. Among the total 124 Stapylococcal isolates, 62 [50%] were Staph. aureus and 62 [50%] were coagulase negative staphylococci. Of the 62 Staph aureus isolates, 35 [56.45%] were from nasal swabs and 27 [43.54%] from throat swabs. Of the 62 coagulase negative Staphylococcus isolates, 44 [70%] were from nasal swab, four [6%] from throat swab and 14 [22%] were from both nasal and throat swabs. The study indicates an alarming prevalence rate of Staph. aureus. Hence we conclude that the data observed reflected the need for a complete revision for all the infection control programs at GMU and GMCH and RC which includes education programs, aseptic techniques, hospital hygiene and periodic microbiological surveillance in order to control the spread of infection

Betalactamase production of Staphylococcus aureus: a comparison study of different iodometric methods

This study was undertaken to detect Beta-lactamase producing Staphylococcus aureus among healthy individuals by using different iodometric methods [filter paper, agar plate and tube]. The study was carried out among 127 normal healthy volunteers of Gulf Medical University and Gulf Medical College Hospital and Research Center, Ajman. Nasal and throat swabs were collected with strict aseptic precautions. All the swabs were examined by direct microscopy and inoculated into appropriate culture media. Staphylococcus aureus was identified by tube coagulase test and growth on MSA. Beta-lactamase enzyme activity of Staph. aureus was determined by the filter paper, agar plate and tube lodometric methods. Antimicrobial susceptibility testing by Kirby-Bauer's method was performed for all Beta-lactamase producing Staph. aureus. Out of 127 healthy volunteers screened, Staph. aureus were isolated from the nasal and throat swabs from 62 subjects. Of the 62 Staph. aureus isolates, 40 [64.5%] were positive by all the three iodometric methods. Six isolates [9.6%] were positive by two methods [4 isolates by filter paper and tube methods, one isolate by filter paper and agar plate methods and one isolate by agar plate and tube methods]. Four isolates [6.4%] were positive by one of these methods. Twelve isolates [19.4%] were totally negative by all the three methods. Overall susceptibility of filter paper and tube methods were found to have similar results 45 [72.5%]. Whereas the overall susceptibility of agar plate method was 42 [67.7%]. Antimicrobial susceptibility was 100% to Vancomycin and Rifampicin, and 100% resistance to Penicillin and Ampicillin. The study indicates that the filter paper and tube iodometric methods were accurate and superior to the agar plate method in the detection of Staphylococcal Beta-lactamase. We conclude that the alarming prevalence rate of Beta-lactamase among normal healthy individuals indicates the need for treatment by Beta-lactamase-susceptible antibiotics