Print this page Email this page
Users Online: 33
Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 4  |  Issue : 2  |  Page : 99-103

Nasal carriage of methicillin-resistant Staphylococcus aureus among hospitalized otorhinolaryngological patients in Benin City of Nigeria


1 Department of Otorhinolaryngology, University of Benin Teaching Hospital, Edo, Nigeria
2 Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Benin, Edo, Nigeria

Date of Web Publication16-Oct-2014

Correspondence Address:
Ngozi Onyeagwara
Department of Otorhinolaryngology, University of Benin Teaching Hospital, Benin, P.M.B 1111 Benin, Edo
Nigeria
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2278-9596.143087

Rights and Permissions
  Abstract 

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has become a major health problem worldwide. MRSA is a common pathogen implicated in Hospital-acquired infection. About 20% of patients undergoing surgery acquire at least one nosocomial infection leading to increased morbidity, mortality, hospital stay and cost of treatment. This study was designed to appraise the incidence of nasal carriage of MRSA among patients admitted for otorhinolaryngological surgical intervention in a teaching hospital.
Patients and Methods: A total of 50 nasal swabs were collected from hospitalized patients at the Otorhinolaryngology Department of the University of Benin Teaching Hospital, South-South region of Nigeria during the period of three months extending from July to September 2012. Each sample was processed using standard microbiological protocols.
Results: In all, 25 (50%) of the isolated organisms were Staphylococcus aureus, 6 (12%) were Staphylococcus epidermidis and 19 (38%) were Staphylococcus lugdunensis. Forty percent of the S. aureus isolated were resistant to methicillin. All the multidrug resistant strains of S. epidermidis and S. lugdunensis were also resistant to methicillin. The isolates showed resistance to the various classes of antimicrobial agents tested with the least against the aminoglycosides.
Conclusion: Our results suggest that a more effective and adequate preparations such as infection control and patients selection are required to reduce the spread of multidrug resistant strains in otorhinolaryngology practice.

Keywords: Methicillin-resistant Staphylococcus aureus, multidrug resistant staphylococcus, otorhinolaryngology


How to cite this article:
Onyeagwara N, Obasuyi O, Ottih I, Akerele JO. Nasal carriage of methicillin-resistant Staphylococcus aureus among hospitalized otorhinolaryngological patients in Benin City of Nigeria . Arch Int Surg 2014;4:99-103

How to cite this URL:
Onyeagwara N, Obasuyi O, Ottih I, Akerele JO. Nasal carriage of methicillin-resistant Staphylococcus aureus among hospitalized otorhinolaryngological patients in Benin City of Nigeria . Arch Int Surg [serial online] 2014 [cited 2020 Oct 21];4:99-103. Available from: https://www.archintsurg.org/text.asp?2014/4/2/99/143087


  Introduction Top


Staphylococcus aureus is both a human commensal and a frequent cause of clinically important infections. [1] Studies have shown that the anterior nares are the most frequent carriage site for S. aureus. [2] The association between S. aureus nasal carriage and Staphylococcal disease was first reported by Danbolt, in 1931, who studied Furunculosis. [3] Staphylococcus aureus causes superficial skin lesions such as boils and furunculosis, acute infections such as pneumonia and urinary tract infections, and deep-seated infections such as osteomyelitis and endocarditis. [4] Since methicillin-resistant Staphylococcus aureus (MRSA) was first reported in 1961, it has been a major nosocomial pathogen worldwide. [5] Currently, hospitals worldwide experience MRSA as a major nosocomial pathogen. [6] In many institutions, approximately 25% to 50% of S. aureus strains and 75% of coagulase-negative staphylococci (CoNS) are resistant to methicillin. [7] The MRSA are of particular concern because of the ease with which certain epidemic strains spread and colonize debilitated immunocompromised patients. Nasal carriage of MRSA has been identified as a significant risk factor for surgical site infections. [8] Jiang et al. found that untreated MRSA are capable of causing mucopurulent crusting and discharge in patients, thereby affecting postoperative outcomes in hospitalized Otorhinolaryngology patients. [9] In Otorhinolaryngology, MRSA are able to cause different kinds of infections like soft tissue infections, post operative infections, otits media, otitis externa, sinusitis which can later develop to chronic rhinosinusitis and mastoiditis. [10],[11] The consequence of increasing MRSA infection could cause longer hospital stay and attendant increased cost, which approximately doubles the expenditure of the patient. [12] The emergence of MRSA to vancomycin has heightened serious health concern and anxieties. [13] Furthermore, MRSA are highly transmissible from healthcare workers to patients and patients to healthcare workers directly or through fomites or instruments. An MRSA outbreak can occur when one strain is transmitted from a patient or healthcare worker to other patients. Few studies however have focused on Otorhinolayngology patients. Thus, the determination of nasal carriage of MRSA among hospitalized Otorhinolaryngological patient as a possible adjunct determinant factor among hospitalized patients is of public health concern especially in developing countries where health facilities are grossly inadequate. This could have a salutary effect on the measures of infection control when properly implemented to prevent spread of this microorganism. In this study, we report the prevalence of MRSA and other staphylococci species in hospitalized Otorhinolaryngology patients, the causal relationship and certain individual parameters such as sex, age and the resistant profile of these isolates to some commonly prescribed antimicrobial agents.


  Patients and Methods Top


Study area

This preliminary study was conducted in Otorhinolaryngology Department of the University of Benin Teaching Hospital, Nigeria during a period of three months extending from July to September 2012. A total of 50 consecutive patients, comprising 25 each from males and females with ages ranging from 0-75 years, who were prepared for surgery and already admitted into the ward with no clinical evidence of active infection, were enrolled for the study with consent and approval from the hospital ethical committee. The upper anterior nares were swabbed using sterile cotton swab sticks and immediately transported to the Pharmaceutical Microbiology Laboratory of the University of Benin Teaching Hospital. The swabs were aseptically cut into tryptic soy broth (TSB) (Scharlau, Spain) and incubated at 37 o C for 24 hours.

Sample processing

A loopful of the overnight culture from TSB was transferred onto the surface of mannitol salt agar (MSA) (Conda Pronadisa, Spain) and 5% blood agar. These were further incubated at 37 o C for 24 hours. The characteristic isolates were aseptically selected and characterized using standard established microbiological methods, which include growth and fermentation on MSA, colonial morphology, Gram-staining reaction and biochemical characteristics. [14] Isolates that were Gram-positive cocci (grape-like clusters), which produce catalase and positive to both slide and tube coagulase tests with human plasma were considered as S. aureus in this study.

Susceptibility test

Antibiotic susceptibility test was carried out by disc diffusion method using antibiotic multi-disc containing amoxicillin 30 μg, ampicillin/cloxacillin 30 μg, ceftriaxone 25 μg, cefuroxime 20 μg, ciprofloxacin 10 μg, pefloxacin 10 μg, gentamicin 10 μg, streptomycin 30 μg, erythromycin 10 μg and sulphamethoxazole/trimethoprim 30 μg. [15]

Identification of methicillin resistance

MSA plates were prepared with cefoxitin at a concentration of 4 mg/L. The test strains were applied in the following way: Suspensions of viable organisms were prepared, matched with 0.5 McFarland standard and a loopful of the suspension spread over the MSA - cefoxitin agar plates. A control plate of blood agar was used for each strain. [14] Incubation was carried out in air at 35°C for 48 hrs and the growth of any visible colonies after incubation was recorded as a positive. Resistance to methicillin (cefoxitin) was conducted on all strains of S. aureus and the multidrug resistant (MDR) strains among other isolated staphylococci species.


  Results Top


Out of a total 50 nasal swabs collected from otorhinolaryngological patients in this study, 25 (50%) yielded S. aureus, 6 (12%) were S. epidermidis and 19 (38%) were S. lugudunensis. Out of the 25 isolates of S. aureus, 10 isolates (40%) were resistant to methicillin; 1 out of 6 and 7 out of 19 among S. epidermidis and S. lugdunensis, respectively were MDR and also showed resistance to methicillin [Table 1]. Multi drug resistance was defined as resistance to three or more classes of antibiotics other than the beta-lactam antibiotics. [Figure 1] shows the resistance profile of the various isolates against the antimicrobial agents tested. The resistance profile of all the MRSA strains was also determined [Figure 2]. The isolates showed high resistance to amoxicillin 100%, ampicillin/cloxacillin 100% and sulphamethoxazole/trimethoprim (100%), ceftriaxone (90%), pefloxacin (90%), cefuroxime (80%) and least resistance to streptomycin (20%), gentamicin (20%) and ciprofloxacin (30%). The distribution of MRSA according to age and sex is shown in [Table 2]. Prevalence of MRSA was higher in females than in males.
Table 1: Frequency of all isolates obtained showing resistance to methicillin

Click here to view
Table 2: Distribution of MRSA among age and sex

Click here to view
Figure 1: Resistance profile of the various isolates. Key: AM = amoxicillin; APX = Ampicillin/cloxacillin, R = Ceftriaxone; Z = Cefuroxime; CPX = Ciprofloxacin; PEF = Pefloxacin; S = Streptomycin; CN = Gentamicin; E = Erythromycin; SXT = Sulphamethoxazole.

Click here to view
Figure 2: Antibiotic resistance profile of the MRSA isolates. Key: AM = Amoxicillin; APX = Ampicillin/cloxacillin, R = Ceftriaxone; Z = cefuroxime; CPX = Ciprofloxacin; PEF = Pefloxacin; S = Streptomycin; CN = Gentamicin; E = Erythromycin; SXT = Sulphamethoxazole.

Click here to view



  Discussion Top


Methicillin-resistant Staphylococcus aureus infections have been attributed to nasal carriage of the organism with the nose acting as the primary ecologic reservoir of S. aureus in humans. [15],[16],[17] Nasal carriage of MRSA has been identified as a significant risk factor for surgical site infections. [14] The difficulty with MRSA lies with the need to use expensive and potentially toxic antibiotics. [18] New, resistant strains and associated infections are becoming prevalent, such as vancomycin-resistant S. aureus (VRSA) and pantonvalentine leukocidin (PVL). [19],[20]

Our study showed a high prevalence of S. aureus (50%) and MRSA (40%) among hospitalized otorhinolaryngology patients. This correlates with Pant and Rai who revealed higher S. aureus nasal colonization rate (43.8%) in the staff of teaching hospital in Nepal. [21] Also, in Abia State of Nigeria, Chigbu and Ezeronye reported 50% nasal colonization in both hospital and non-hospital subjects. [22] The frequency of MRSA in this study also correlates with that of Taiwo et al, and Olowe et al., who reported 47.8% prevalence of MRSA from clinical specimens. [23],[24] This high prevalence of MRSA with these patients should obviously elicit genuine concern. Most of the patients had undergone surgical procedures like tonsillectomy. From previous studies, the prevalence of MRSA was estimated to be higher in surgical patients (5.1%) as compared to the general public. [25],[26] Recent use of broadspectrum antibiotics for surgical prophylaxis may have predisposed these groups of patients to high proliferation of MRSA. These patients are posed with increased risk and the likelihood of coming in contact with patients and healthcare workers who are already colonized by MRSA. The permanent presence of friends and relatives, peculiarly observed with hospital settings in the study area, who share some healthcare responsibilities for these patients, could have increased the risk of MRSA circulation between the community and hospital settings.

We also found that MRSA isolates in the patients showed complete resistance (100%) to the penicillins, amoxicillin and ampicillin/cloxacillin, and sulphamethoxazole/trimethoprim. The possible reason could be attributed to the relatively low cost of the drugs in the Nigerian market, ease of delivery, readily available, minimal side effects, and are generally available without prescriptions. Ciprofloxacin had a better antimicrobial activity against the MRSA isolates as compared to pefloxacin even though they belong to the same class of fluoroquinolones. The least resistance was observed with streptomycin (20%) and gentamicin (20%), both of which are aminoglycosides. The possible reason is that they are less commonly prescribed due to their toxicity such as ototoxicity, relatively expensive and are mostly given intramuscularly or intravenously. The implication of these is that the aminoglycosides may be the drug of choice for the treatment of infections due to MRSA in this study area. It was observed that a higher rate of MRSA was found in females as opposed to the males and among advanced age ≥46. Maria et al., in their study for age and gender associated S. aureus types among nasal carriers in a general population, found that there was no association between S. aureus genotype and host attribute such as gender and age. [27] Our study also revealed the carriage of multidrug resistant Coagulase-negative staphylococci (CoNS) and S. lugdunensis, which were resistant to methicillin as well. This agrees with the findings of Smyth and Kahlmeter who reported that more frequently, patient specimens yielded methicillin-resistant (and cefoxitin-resistant) CoNS. [16] MRSA are of particular concern because of the ease with which certain epidemic strains spread and colonize debilitated immunocompromised patients. Nasal carriage of MRSA has been identified as a significant risk factor for surgical site infections. [8],[28] Untreated MRSA can cause mucopurulent crusting and discharge in patients, affecting postoperative outcomes in hospitalized Otorhinolaryngology patient. [9] In Otorhinolaryngology, MRSA can cause different kinds of infections like soft tissue infections, post operative infections, otits media, otitis externa, sinusitis which can later develop to chronic rhinosinusitis and mastoiditis. [10],[11] The consequence of increasing MRSA infection could cause longer hospital stay and attendant increased cost, which approximately doubles the expenditure per patient. [12] The emergence of MRSA to vancomycin has heightened serious health concern and anxieties. [13]


  Conclusion Top


Control of MRSA infections is essential, and it can be achieved by proper implementation of hospital infection control measures, regular surveillance activity and proper documentation to prevent further transmission. Health care and infection control personnels should remain vigilant and continually develop protocols for minimizing microbial transmission. These findings call for pro-active serious concern, as they serve as additional disposing factors in the post-surgical managements of the patients. This calls for strategies for reduction and possible elimination of nasal carriage of S. aureus and incidence of S. aureus infections.

 
  References Top

1.
Lowy FD. Staphylococcus aureus infections. N Engl J Med 1998;339:520-32.  Back to cited text no. 1
    
2.
Wertheim HF, Melles DC, Vos MC, van Leeuwen W, van Belkum A, Verbrugh HA, et al. The role of nasal carriage in staphylococcus aureus infection. Lancet infect Dis 2005;5:751-62.  Back to cited text no. 2
    
3.
Solberg CO. A study of carriers of Staphylococcus aureus with special regard to quantitative estimations. Acta Med Scand Suppl 1965;436:1-96.  Back to cited text no. 3
    
4.
Ellis MW, Hospenthal DR, Dooley DP, Gray PJ, Murray CK Natural history of community-acquired methicillin-resistant Staphylococcus aureus colonization and infection in soldiers. Clin Infect Dis 2004;39:971-9.   Back to cited text no. 4
    
5.
Huang SS, Diekema DJ, Warren DK, Zuccotti G, Winokur PL, Tendolkar S, et al. Genetic relatedness of multidrug-resistant, methicillin-resistant Staphylococcus aureus bloodstream isolates from SENTRY Antimicrobial Resistance Surveillance centers worldwide, 1998. Microb Drug Resist 2000;6:213-21.  Back to cited text no. 5
    
6.
Cohen J, Powderly WG. Infectious diseases. 2 nd ed. St Louis: Mosby; 2004.  Back to cited text no. 6
    
7.
York MK, Gibbs L, Chehab F, Brooks GF. Comparison of PCR detection of mecA with standardized susceptibility testing methods to determine methicillin resistance in coagulase negative Staphylococci. J Clin Microbiol 1996;34:249-53.  Back to cited text no. 7
    
8.
Kluytmans J, van Belkum A, Verbrugh H. Nasal carriage of Staphylococcus aureus epidemiology, underlying mechanisms and associated risks. Clin Mibrobiol Rev 1997;10:505-20.  Back to cited text no. 8
    
9.
Jiang RS, Jang JW, Hsu CY. Post-functional endoscopic sinus surgery methicillin-resistant Staphylococcus aureus sinusitis. Am J Rhinol 1999;13:273-7.  Back to cited text no. 9
    
10.
Tabaee A, Anand VK, Yoon C. Outpatient intravenous antibiotics for methicillin-resistant Staphylococcus aureus sinusitis. Am J Rhinol 2007;21:154-8.  Back to cited text no. 10
    
11.
Solares CA, Batra PS, Hall GS, Citardi MJ. Treatment of chronic rhinosinusitis exacerbations due to methicillin-resistant Staphylococcus aureus with mupirocin irrigations. Am J Otolaryngol 2006;27:161-5.  Back to cited text no. 11
    
12.
Kim T, Oh PI, Simor AE. The economic impact of methicillin-resistant Staphylococcus aureus in Canadian hospital. Infect Control Hosp Epidemiol 2001;22:267-9.  Back to cited text no. 12
    
13.
Hiramatsu K, Aritaka N, Kawaski S, Hosoda Y, Hori S. Dissemination in Japanese hospitals of strains of Staphylococcus aureus heterogeneously resistant to vancomycin. Lancet 1997;350:1670-3.   Back to cited text no. 13
    
14.
Cheesbrough M. District Laboratory Practice in Tropical Countries. Part 2: Cambridge University Press. Cambridge CBZ ZRU, UK. 2002. p. 64-68, 136-142.  Back to cited text no. 14
    
15.
Bauer WA, Kirby WM, Sherris JC, Truck M. Antibiotics susceptibility by standardized disc method. Am J Clin Pathol 1966;45:493-6.  Back to cited text no. 15
    
16.
Smyth RW, Kahlmeter G. Mannitol salt agar-cefoxitin combination as a screening medium for methicillin-resistant Staphylococcus aureus. J Clin Microbiol 2005;43:3797-9.  Back to cited text no. 16
    
17.
Luzar MA, Coles GA, Faller B, Slingeneyer A, Dah GD, Briat C, et al. Staphylococcus aureus nasal carriage and infection in patients on continuous ambulatory peritoneal dialysis. N Engl J Med 1990;322:505-9.  Back to cited text no. 17
    
18.
Yu VL, Goetz A, Wagener M, Smith PB, Rihs JD, Hanchett J, et al. Staphylococcus aureus nasal carriage and infection in patients on hemodialysis. Efficacy of antibiotic prophylaxis. N Engl J Med 1986;315:91-6.  Back to cited text no. 18
    
19.
Nguyen MH, Kauffman CA, Goodman RP, Squier C, Arbeit RD, Singh N, et al. Nasal carriage of and infection with Staphylococcus aureus in HIV-infected patients. Ann Intern Med 1999;130:221-5.  Back to cited text no. 19
    
20.
Biant LC, Teare EL, Willians WW, Tuite JD. Eradication of methicillin resistant Staphylococcus aureus by "ring fencing" of elective orthopaedic beds. BMJ 2004;329:149-51.  Back to cited text no. 20
    
21.
Chang S, Sievert DM, Hageman JC, Boulton ML, Tenover FC, Downes FP, et al.; Vancomycin-Resistant Staphylococcus aureus Investigative Team. Infection with vancomycin resistant Staphylococcus aureus containing the vanA resistance gene. N Engl J Med 2003;348:1342-7.  Back to cited text no. 21
    
22.
Troche G, Joly LM, Guibert M, Zazzo JF. Detection and treatment of antibiotic-resistant bacteria carriage in a surgical intensive care unit: A 6-year prospective survey. Infect Control Hosp Epidemiol 2005;26:161-5.  Back to cited text no. 22
    
23.
Pant J, Rai SK. Occurrence of Staphyloccous aureus in hospital environment and staffs in teaching hospital in Katmandu, Nepal. J Nepal Assoc Med Lab Sci 2007;72-3.  Back to cited text no. 23
    
24.
Chigbu CO, Ezeronye OU. Antibiotic resistant Staphyloccous aureus in Abia State of Nigeria. Afr J Biotech 2003;2:374-8.  Back to cited text no. 24
    
25.
Taiwo SS, Bamidele M, Akinside KA, Omonigbehin EA, Smith SI, Onile BA, et al. Molecular epidemiology of methicillin resistant Staphylococcus aureus in Ilorin, Nigeria. West Afr J Med 2005;24:100-6.  Back to cited text no. 25
    
26.
Olowe OA, Eniola KI, Olowe RA, Olayemi AB. Antimicrobial susceptibility and Beta-lactamase detection of MRSA in Osogbo, SW Nigeria. Nat Sci 2007;5:44-8.   Back to cited text no. 26
    
27.
Morange-Saussier V, Giraudeau B, van der Mee N, Lermusiaux P, Quentin R. Nasal carriage of methicillin-resistant Staphylococcus aureus in vascular surgery. Ann Vasc Surg 2006;20:767-72.  Back to cited text no. 27
    
28.
Maria S, Renate SO, Karina O, Gunnar SS, Anne-Sophie F, Johanna U. Age and Gender associated Staphylococcus aureus spa types found among nasal carriers in a general population: The Tromso Staph and skin study. J Clin Microbiol 2011;49:4213-8.  Back to cited text no. 28
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Patients and Methods
Results
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed1506    
    Printed35    
    Emailed0    
    PDF Downloaded175    
    Comments [Add]    

Recommend this journal