Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Visit old site
Home Print this page Email this page Small font size Default font size Increase font size
Users Online: 2228


 
 Table of Contents  
ORIGINAL ARTICLE
Year : 2014  |  Volume : 6  |  Issue : 8  |  Page : 403-407

Prevalence of mupirocin resistant Staphylococcus aureus isolates among patients admitted to a tertiary care hospital


1 Department of Microbiology, Mayo Institute of Medical Sciences, Barabanki, Uttar Pradesh, India
2 Department of Microbiology, Major SD Singh Medical College and Hospital, Farrukhabad, Uttar Pradesh, India
3 Department of Microbiology, Mayo Institute of Medical Sciences, Barabanki, Uttar Pradesh

Date of Web Publication20-Aug-2014

Correspondence Address:
Amit Kumar Singh
Department of Microbiology, Mayo Institute of Medical Sciences, Barabanki, Uttar Pradesh
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1947-2714.139293

Rights and Permissions
  Abstract 

Background: For the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections and decolonization of MRSA carriers, the use of mupirocin a topical antibiotic is increasing day by day. Aim: The present study was carried out to determine the prevalence rate of high-level and low-level mupirocin resistant MRSA isolates among patients admitted to a tertiary care hospital. Materials and Methods: This is a prospective study carried out on MRSA isolated from the various clinical specimens from outpatient and inpatient departments during period of one year. A total of 82 MRSA isolates were recovered from 6468 different clinical specimens. Mupirocin resistant MRSA was detected by two different methods: Epsilometer test (E-test) and agar dilution method. D-shaped zone test (D-zone test) was also performed for determination of inducible clindamycin resistance in MRSA isolates. Results: Out of 82 non-duplicate MRSA isolates mupirocin resistance were found in 15 (18.3%) isolates by both E-test and agar dilution method. Of these 15 mupirocin resistant, 8 (53.3%) isolates were high-level resistant (MuH) and 7 (46.7%) isolates were low-level resistant (MuL). Four isolates were D-zone test positive showing simultaneous inducible clindamycin resistance among mupirocin resistant MRSA isolates. Conclusion: Higher prevalence of both high-level and low-level of mupirocin resistant MRSA was observed in patient from the population. It is advisable to perform routine test to detect MRSA colonization among health care workers and nasal decolonization to prevent spread of MRSA infections among hospitalized patients.

Keywords: High-level, MRSA, MuH, MuL, Mupirocin resistance, Low-level


How to cite this article:
Chaturvedi P, Singh AK, Singh AK, Shukla S, Agarwal L. Prevalence of mupirocin resistant Staphylococcus aureus isolates among patients admitted to a tertiary care hospital. North Am J Med Sci 2014;6:403-7

How to cite this URL:
Chaturvedi P, Singh AK, Singh AK, Shukla S, Agarwal L. Prevalence of mupirocin resistant Staphylococcus aureus isolates among patients admitted to a tertiary care hospital. North Am J Med Sci [serial online] 2014 [cited 2019 Nov 13];6:403-7. Available from: http://www.najms.org/text.asp?2014/6/8/403/139293


  Introduction Top


Staphylococcus aureus infections are one of the most common and serious hospital-acquired infections seen in developing countries. [1],[2],[3] Various studies have shown an increased prevalence of staphylococcus infections which may be attributed to its carriage in anterior nares and hands of health care workers and patients. [4],[5] Along with that drug resistance seen in cases of Staphylococcus aureus infections is a great concern for the clinicians to prevent spread of infections. Methicillin an important drug of penicillin group was commonly used for these infections before the emergence of methicillin-resistant Staphylococcus aureus (MRSA) strains. [6] The important risk factors for development of MRSA are irrational use of antibiotic, prolong duration of hospital stay, nasal and hand carriage in health care staff. [7],[8]

Vancomycin and linezolid are commonly used antibiotics for MRSA infections whereas mupirocin a topical antibiotic is used for treatment of skin and soft tissue infections as well as decolonization of carriers. [9],[10] It inhibits the protein synthesis by binding specifically to isoleucyl-tRNA synthetase enzyme. [11] The increased pressure of MRSA infections among patients and its carriage in health care staff has led to indiscriminate use of mupirocin which has resulted in emergence of its resistance. [10] Phenotypically mupirocin resistant strains are grouped into low-level (MuL) resistance and high-level (MuH) resistance phenotypes. [11] The minimum inhibitory concentrations (MIC) are <4 μg/ml, 8-256 μg/ml and >512 μg/ml for mupirocin sensitive, low-level resistance and high-level resistance respectively. [12] Although there is no guideline for detection of mupirocin resistance, traditionally disc diffusion method using 5 μg and 200 μg mupirocin disc, agar dilution method and broth micro dilution method have been used. [13]

Various studies have suggested that treatment of infections with low-level resistant strains is still possible with normal dosage schedule of 0.2% mupirocin ointment. [14] Whereas, high-level resistant strains are frequently associated with failure of decolonization as well as treatment of skin and soft tissues infections. [15],[16],[17] Thus the present study was aimed to determine the prevalence of high-level mupirocin resistance strains, low-level mupirocin resistance strains and mupirocin sensitive phenotypes.


  Material and Methods Top


MRSA isolates recovered from clinical specimens such as pus, blood, urine, tracheal aspirate, wounds swab, surgical pus and synovial fluid from patients who attended various outpatient departments or admitted to various wards of Mayo Institute of Medical Sciences, Barabanki, UP, India during one year period from May 2013 to April 2014 were included in the study. Informed consent was obtained from each patient and a detailed clinical history and demographic profile was taken and recorded from the patients whose culture was positive for MRSA.

Isolation and identification of MRSA

Clinical specimens obtained in the microbiology laboratory were processed as per routine microbiological procedures for isolation and identification of Staphylococcus aureus. All the clinical specimens excluding urine were inoculated on 5% sheep blood agar and MacConkey agar media, whereas urine samples were inoculated on Cysteine-lactose electrolyte deficient (CLED) agar media and incubated at 37 o C aerobically. The growth was identified as Staphylococcus aureus by using conventional biochemical methods according to standard microbiological techniques.

Detection of MRSA

MRSA was detected by using cefoxitin (30 μg) disc as per Clinical and Laboratory Standards Institute (CLSI) guidelines. [18] A lawn culture was made on Mueller-Hinton agar (MHA) with 4% NaCl from suspension of turbidity equivalent to 0.5 MacFarland Standards from overnight growth in nutrient agar and incubated for 24 hours aerobically at 35 o C. After incubation the plates were examined for zone of inhibition. Zone of inhibition ≥22 mm was considered as sensitive and such isolates were excluded from the study, whereas ≤21 was considered as resistant and reported as a MRSA and included in the study.

Antimicrobial susceptibility testing of MRSA

Antimicrobial susceptibility testing was done according to the CLSI guidelines by Kirby-Bauer disc diffusion method for the following antibiotics: Cefuroxime (30 μg), cephalothin (30 μg), clindamycin (2 μg), cotrimoxazole (1.25/23.75 μg), erythromycin (15 μg), oxacillin (1 μg), penicillin (10 units), chloramphenicol (30 μg), linezolid (30 μg), vancomycin (30 μg). [18] Four to five morphological identical colonies picked from overnight growth in nutrient agar, were inoculated into 5 ml of peptone water and incubated at 37 o C until turbid and compared with 0.5 McFarland Standards. After standardization of turbidity, using a sterile cotton swab a lawn culture was done on the surface of MHA. Antibiotic discs were applied by pressing gently using a sterile forceps on the surface of media and placed at least 20 mm apart from each other.

Epsilometer test (E-test) for determination of minimum inhibitory concentration for mupirocin

E-test was performed by Kirby Bauer disc-diffusion method as per CLSI guidelines by using HiComb mupirocin strip. [18] Lawn culture was made on the surface of MHA medium. HiComb strip with mupirocin antibiotic ranges from 0.1-240 μg/ml was applied perfectly by gently pressing using a sterile forceps. The plates were then incubated aerobically at 35 o C for 24 hours. After incubation plates were examined for the minimum inhibitory concentration (MIC). Isolates with MICs > 512 μg/ml were considered as MuH, those with MICs 8-256 μg/ml were considered as MuL and with <4 μg/ml were considered as mupirocin sensitive.

Agar dilution method for determination of MIC for mupirocin

Agar dilution method was performed by doubling dilution of mupirocin incorporated in MHA plate. A suspension of turbidity equivalent to 0.5 MacFarland Standards was prepared from overnight growth of Staphylococcus aureus on nutrient agar. The surface of each MHA plate was inoculated with 1 μl of suspension and plate was incubated at 37 o C aerobically for 24 hours. Plates were examined for growth and compared with positive growth control plate without the antibiotic agent, more than one colony or light film of growth was considered as mupirocin resistant. By this method, more than one bacteria were tested per plate. MIC values were same as used for E-test.

D-shaped zone test (D-test) for determination of inducible clindamycin resistance

D-test was performed for determination of inducible clindamycin resistance in MRSA isolates. While performing antimicrobial susceptibility testing, erythromycin disk was placed in close proximity (20 mm) to clindamycin disk. After 16-18 hours of incubation the plates were observed for flattening of the zone of inhibition adjacent to the erythromycin disk (referred to as a D-zone) which indicates inducible clindamycin resistance. These isolates were reported as resistant to clindamycin. Hazy growth within the zone of inhibition around clindamycin was also considered as clindamycin resistance, even if no D-zone is apparent. [18]

Statistical analysis

All the data were recorded in Microsoft excel sheet. Data were analyzed statistically by using Chi-square test to calculate significant levels. P values <0.05 were considered statistically significant.


  Results Top


A total of 361 Staphylococcus aureus were obtained from 6468 different clinical samples. Among 361 Staphylococcus aureus, 82 isolates were MRSA. MRSA isolates were obtained in highest number from pus (72%) followed by sputum (8.5%), urine (7.3%) and blood (6.1%). Distribution of Staphylococcus aureus and MRSA on the basis of source of specimen is listed in [Table 1].
Table 1: Distribution of Staphylococcus aureus and MRSA on the basis of source

Click here to view


Out of 82 MRSA isolates, mupirocin resistance were seen in 15 (18.3%) isolates by both E-test and agar dilution method. Of these 15 mupirocin resistant MRSA, 8 (53.3%) isolates were MuH and 7 (46.7%) isolates were MuL [Table 2]. Four isolates were D-zone test positive showing simultaneous inducible clindamycin resistance among mupirocin resistant MRSA isolates.
Table 2: Mupirocin resistant Staphylococcus aureus
among MRSA isolates (n = 82)


Click here to view


[Table 3] shows the antimicrobial susceptibility profile of MRSA isolates. In this study, it is observed that MRSA isolates were resistant to 88.4%, 55.9%, 44.2%, and 40.3% of penicillin, cotrimoxazole, cephalothin, and cefuroxime respectively. Vancomycin and linezolid were uniformily sensitive to all MRSA isolates.
Table 3: Antimicrobial resistance patt ern of MRSA and Mupirocin-resistant MRSA isolates (n = 82)

Click here to view



  Discussion Top


MRSA is one of the leading cause of infections among health care staff and hospitalized patients. It also causes community associated infections. It causes a wide range of infections such as abscesses, impetigo, cellulitis, deep seated pyogenic lesions, meningitis, septicaemia, and pneumonia. [19] Prevalence of MRSA infections may increase because of improper hand hygiene and handling of MRSA carrier patients. Mupirocin is a commonly used antibiotic for decolonization of MRSA in carriers and for treatment of skin and soft tissue infections caused by MRSA. [9],[10] Emergence of mupirocin resistance due to its irrational use for treatment of skin and soft tissue infections is further worsening the problem of MRSA infections. Studies also suggest that mupirocin resistance may be transferred from the commensal flora of skin to MRSA during mupirocin therapy. [20] In this study, a total of 82 (22.7%) MRSA isolates were obtained from 361 Staphylococcus aureus. The prevalence is quite low as compared to several other studies conducted in this region. [1],[21] This may be attributed to lesser exposure to antibiotics due to low-level of healthcare facilities in this region in past years.

Among 82 MRSA isolates, 15 (18.3%) isolates were mupirocin resistant which is high as compared to other studies conducted in this region. [22],[23] The reason for higher prevalence of mupirocin resistance may be an increased use of mupirocin ointment for skin and soft tissue infections. Eight (9.7%) MuH and 7 (8.5%) MuL MRSA isolates determined by two different MIC methods were comparable. Whereas MuL isolates may be treated with normal dosage schedule of mupirocin ointment, but MuH has been found to be associated with treatment and decolonization failure. [14],[15],[16],[17]

In this study 4 (4.9%) mupirocin resistant MRSA isolates were showing D-test positive indicating inducible clindamycin resistance. This is low in comparison to several studies conducted in different regions. [24],[25],[26] Antibiotic susceptibility pattern of MRSA and mupirocin-resistant MRSA isolates showed no significant association of methicillin resistance and mupirocin resistance with resistance to other antibiotics in this study.


  Conclusion Top


The study has demonstrated a higher prevalence of both MuH and MuL in MRSA isolates which is a serious challenge to the clinicians to deal with increasing problem of MRSA transmission in the hospital. This may be due to an increased prevalence of MRSA infections in the health care setup and over the counter sale of drugs. Mupirocin resistance along with MRSA resistance may enhance the spread of infections. Thus it is advisable to routinely perform nasal decolonization of health care workers to prevent spread of infections among hospitalized patients and to detect mupirocin resistance in MRSA strains isolated from the carriers so that alternative decolonization methods may be used.

 
  References Top

1.Joshi S, Ray P, Manchanda V, Bajaj J, Chitnis DS, Gautam V, et al. Methicillin-resistant Staphylococcus aureus (MRSA) in India: Prevalence and susceptibility pattern. Indian J Med Res 2013;137:363-9.   Back to cited text no. 1
    
2. Dubey D, Rath S, Sahu MC, Pattnaik L, Debata NK, Padhy RN. Surveillance of infection status of drug resistant Staphylococcus aureus in an Indian teaching hospital. Asian Pac J Trop Dis 2013;3:133-42.   Back to cited text no. 2
    
3.Kaur H, Purwar S, Saini A, Kaur H, Karadesai SG, Kholkute SD, Roy S. Status of Methicillin-resistant Staphylococcus aureus Infections and Evaluation of PVL Producing Strains in Belgaum, South India. JKIMSU 2012;1:43-51.   Back to cited text no. 3
    
4. Sivaraman K, Venkataraman N, Cole AM. Staphylococcus aureus Nasal Carriage and its Contributing Factors. Future Microbiol 2009;4:999-1008.   Back to cited text no. 4
    
5. Wertheim HF, Melles DC, Vos MC, van Leeuwen W, van Belkum A, Verbrugh HA, et al. The role of nasal carriage in Staphylococcus aureus infections. Lancet Infect Dis 2005;5:751-62.   Back to cited text no. 5
    
6. Rayner C, Munckhof WJ. Antibiotics currently used in the treatment of infections caused by Staphylococcus aureus. Intern Med J 2005;35:S3-16.   Back to cited text no. 6
    
7. Klutymans J, van Balkum A, Verbrughi H. Nasal carriage of Staphylococcus aureus: Epidemiology, underlying mechanisms and associated risk. Clin Microbiol Rev 1997;10:505-20.   Back to cited text no. 7
    
8. Graffunder EM, Venezia RA. Risk factors associated with nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection including previous use of antimicrobials. J Antimicrob Chemother 2002;49:999-1005.   Back to cited text no. 8
    
9. Rodvold KA, McConeghy KW. Methicillin-resistant Staphylococcus aureus therapy: Past, present, and future. Clin Infect Dis 2014;58:S20-7.   Back to cited text no. 9
    
10.Hogue JS, Buttke P, Braun LE, Fairchok MP. Mupirocin resistance related to increasing mupirocin use in clinical isolates of methicillin-resistant Staphylococcus aureus in a pediatric population. J Clin Microbiol 2010;48:2599-600.   Back to cited text no. 10
    
11.Yanagisawa T, Lee JT, Wu HC, Kawakami M. Relationship of protein structure of isoleucyl-tRNA synthetase with pseudomonic acid resistance of Escherichia coli. A proposed mode of action of pseudomonic acid as an inhibitor of isoleucyl-tRNA synthetase. J Biol Chem 1994;269:24304-9.   Back to cited text no. 11
    
12.de Oliveira NE, Cardozo AP, Marques De A, dos Santos KR, Giambiagi-deMarval M. Interpretive criteria to differentiate low- and high-level mupirocin resistance in Staphylococcus aureus. J Med Microbiol 2007;56:937-9.   Back to cited text no. 12
    
13.Patel JB, Gorwitz RJ, Jernigan JB. Mupirocin resistance. Clin Infect Dis 2009;49:935-41.   Back to cited text no. 13
    
14.Hudson IR. The efficacy of intranasal mupirocin in the prevention of staphylococcal infections: A review of recent experience. J Hosp Infect 1994;27:81-98.   Back to cited text no. 14
[PUBMED]    
15. Walker ES, Vasquez JE, Dula R, Bullock H, Sarubbi FA. Mupirocin-resistant, methicillin-resistant Staphylococcus aureus: Does mupirocin remain effective? Infect Control Hosp Epidemiol 2003;24:342-6.   Back to cited text no. 15
    
16.Simor AE, Phillips E, McGeer A, Konvalinka A, Loeb M, Devlin HR, et al. Randomized controlled trial of chlorhexidine gluconate for washing, intranasal mupirocin, and rifampin and doxycycline versus no treatment for the eradication of methicillin-resistant Staphylococcus aureus colonization. Clin Infect Dis 2007;44:178-85.  Back to cited text no. 16
    
17.Robicsek A, Beaumont JL, Thomson RB Jr, Govindarajan G, Peterson LR. Topical therapy for methicillin-resistant Staphylococcus aureus colonization: Impact on infection risk. Infect Control Hosp Epidemiol 2009;30:623-32.   Back to cited text no. 17
    
18. CLSI. Performance Standards for Antimicrobial Susceptibility Testing; Twenty-Third Informational Supplement. CLSI document M100-S23. Vol 33. Wayne: Clinical and Laboratory Standards Institute; 2013. p. 74-85.   Back to cited text no. 18
    
19. Gordon RJ, Lowy FD. Pathogenesis of methicillin-resistant Staphylococcus aureus infection. Clin Infect Dis 2008;46: S350-9.   Back to cited text no. 19
    
20. Hurdle JG, O Neill AJ, Mody L, Chopra I, Bradley SF. In vivo transfer of high-level mupirocin resistance from Staphylococcus epidermidis to methicillin-resistant Staphylococcus aureus associated with failure of mupirocin prophylaxis. J Antimicrob Chemother 2005;56:1166-8.   Back to cited text no. 20
    
21. Arora S, Devi P, Arora U, Devi B. Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in a tertiary care hospital in northern India. J Lab Physicians 2010;2:78-81.   Back to cited text no. 21
[PUBMED]  Medknow Journal  
22. Singh AK, Venkatesh V, Singh M. Mupirocin resistance in clinical isolates of Staphylococcus aureus in a tertiary care hospital set up in north India. Int J Med Res Health Sci 2013;2:840-7.  Back to cited text no. 22
    
23. Gadepalli R, Dhawan B, Mohanty S, Kapil A, Das BK, Chaudhry R, et al. Mupirocin resistance in Staphylococcus aureus in an Indian hospital. Diagn Microbiol Infect Dis 2007;58:125-7.   Back to cited text no. 23
    
24. Gadepalli R, Dhawan B, Mohanty S, Kapil A, Das BK, Chaudhry R. Inducible clindamycin resistance in clinical isolates of Staphylococcus aureus. Indian J Med Res 2006;123: 571-3.   Back to cited text no. 24
[PUBMED]  Medknow Journal  
25. Gupta V, Datta P, Rani H, Chander J. Inducible clindamycin resistance in Staphylococcus aureus: A Study from North India. J Postgrad Med 2009;55:176-9.   Back to cited text no. 25
[PUBMED]  Medknow Journal  
26. Prabhu K, Rao S, Rao V. Inducible clindamycin resistance in Staphylococcus aureus isolated from clinical samples. J Lab Physicians 2011;3:25-7.  Back to cited text no. 26
[PUBMED]  Medknow Journal  



 
 
    Tables

  [Table 1], [Table 2], [Table 3]


This article has been cited by
1 In vitro antibacterial activity of plumbagin isolated from Plumbago zeylanica L. against methicillin-resistant Staphylococcus aureus
H. Periasamy,S. Iswarya,N. Pavithra,S. Senthilnathan,A. Gnanamani
Letters in Applied Microbiology. 2019;
[Pubmed] | [DOI]
2 A review on mechanism of action, resistance, synergism, and clinical implications of mupirocin against Staphylococcus aureus
Saeed Khoshnood,Mohsen Heidary,Arezoo Asadi,Saleh Soleimani,Moloudsadat Motahar,Mohammad Savari,Morteza Saki,Mahtab Abdi
Biomedicine & Pharmacotherapy. 2019; 109: 1809
[Pubmed] | [DOI]
3 Low prevalence of mupirocin resistance in Staphylococcus pseudintermedius isolates from canine pyoderma in Korea
Ji-Hyung Park,Jung-Hun Kang,Jae-Eun Hyun,Cheol-Yong Hwang
Veterinary Dermatology. 2018;
[Pubmed] | [DOI]
4 Antimicrobial Resistance to Agents Used for Staphylococcus aureus Decolonization: Is There a Reason for Concern?
Gregory R. Madden,Costi D. Sifri
Current Infectious Disease Reports. 2018; 20(8)
[Pubmed] | [DOI]
5 The effect of fennel essential oil in combination with antibiotics on Staphylococcus aureus strains isolated from carriers
Pawel Kwiatkowski,Magdalena Mnichowska-Polanowska,Agata Pruss,Helena Masiuk,Malgorzata Dzieciol,Stefania Giedrys-Kalemba,Monika Sienkiewicz
Burns. 2017; 43(7): 1544
[Pubmed] | [DOI]
6 Infection Prevention Strategy in Hospitals in the Era of Community-Associated Methicillin-Resistant Staphylococcus aureus in the Asia-Pacific Region: A Review
Sun Young Cho,Doo Ryeon Chung
Clinical Infectious Diseases. 2017; 64(suppl_2): S82
[Pubmed] | [DOI]
7 Correlation of mupirocin resistance with biofilm production in methicillin-resistant Staphylococcus aureus from surgical site infections in a tertiary centre, Egypt
Ghada I. Barakat,Yasmin M. Nabil
Journal of Global Antimicrobial Resistance. 2016; 4: 16
[Pubmed] | [DOI]
8 Colonization by methicillin resistant staphylococci of nares and skin in healthcare workers: a pilot study in spinal surgeries
Lorenzo Drago,Laura Cappelletti,Claudio Lamartina,Pedro Berjano,Roberto Mattina,Elena De Vecchi
Injury. 2015; 46: S77
[Pubmed] | [DOI]



 

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
Material and Methods
Results
Discussion
Conclusion
References
Article Tables

 Article Access Statistics
    Viewed2085    
    Printed54    
    Emailed0    
    PDF Downloaded388    
    Comments [Add]    
    Cited by others 8    

Recommend this journal