Evaluation of various phenotypic methods with genotypic screening for detection of methicillin-resistant Staphylococcus aureus

Loganathan, Archana; Manohar, Prasanth; Eniyan, Kandasamy; Jayaraj, Rama; Nachimuthu, Ramesh

doi:10.1515/abm-2019-0065

Abstract

Background

Staphylococcus aureus is one of the common opportunistic gram-positive pathogens which are often associated with nosocomial infections. Detection of methicillin-resistant S. aureus (MRSA) has become complicated due to the complex phenotypic and genomic pattern.

Objective

To evaluate the sensitivity and specificity pattern of various phenotypic methods used in screening mec genes harboring MRSA.

Methods

Clinical isolates of S. aureus were collected from diagnostic centers in Tamil Nadu. Phenotypic identification methods such as Minimal Inhibitory Concentration for oxacillin, oxacillin screen agar (OSA), oxacillin disk diffusion, and cefoxitin disk diffusion (CFD) tests were compared. The clinical isolates were classified into MRSA and methicillin-susceptible S. aureus (MSSA) based on the polymerase chain reaction (PCR) amplification of the mecA gene.

Result

Out of 50 S. aureus, 21 were found to be MRSA based on the presence of the mecA gene. All 21 mecA-positive isolates were found to be resistant through minimum inhibitory concentration (MIC) and CFD test, having a sensitivity of 100% and specificity of 52% and 62%, respectively. OSA and oxacillin disk tests were found to have a sensitivity of 86% and specificity of 48% and 52%, respectively.

Conclusion

The combination of two phenotypic methods, CFD and oxacillin MIC, can be used for the detection of MRSA in clinical laboratories.

References

Davis KA, Stewart JJ, Crouch HK, Florez CE, Hospenthal DR. Methicillin-resistant Staphylococcus aureus (MRSA) nares colonization at hospital admission and its effect on subsequent MRSA infection. Clin Infect Dis. 2004; 39:776–82.
Search in Google Scholar Back to article
Enright MC, Robinson DA, Randle G, Feil EJ, Grundmann H, Spratt BG. The evolutionary history of methicillin-resistant Staphylococcus aureus (MRSA). Proc Natl Acad Sci U S A. 2002; 99:7687–92.
Search in Google Scholar Back to article
World Health Organization. Global priority list of antibiotic-resistant bacteria to guide research, discovery, and development of new antibiotics. [online] 2017. [cited 2018 Jan 11]. Available from: http://www.who.int/mediacentre/news/releases/2017/bacteria-antibiotics-needed/en/
Search in Google Scholar Back to article
Popovich KJ, Weinstein RA, Hota B. Are community-associated methicillin-resistant Staphylococcus aureus (MRSA) strains replacing traditional nosocomial MRSA strains? Clin Infect Dis. 2008; 46:787–94.
Search in Google Scholar Back to article
Indian Network for Surveillance of Antimicrobial Resistance (INSAR) group, India. Methicillin resistant Staphylococcus aureus (MRSA) in India: prevalence and susceptibility pattern. Indian Network for Surveillance of Antimicrobial Resistance [INSAR] group, India. Indian J Med Res. 2013; 137:363–9.
Search in Google Scholar Back to article
Basanisi MG, La Bella G, Nobili G, Franconieri I, La Salandra G. Genotyping of methicillin-resistant Staphylococcus aureus (MRSA) isolated from milk and dairy products in south Italy. Food Microbiol. 2017; 62:141–6.
Search in Google Scholar Back to article
Kriegeskorte A, Ballhausen B, Idelevich EA, Köck R, Friedrich AW, Karch H, et al. Human MRSA isolates with novel genetic homolog, Germany. Emerging Infect Dis. 2012; 18:1016.
Search in Google Scholar Back to article
Argudín MA, Roisin S, Nienhaus L, Dodémont M, de Mendonça R, Nonhoff C, et al. Genetic diversity among S. aureus isolates showing oxacillin and/or cefoxitin resistance not linked to the presence of mec genes. Antimicrob Agents Chemother. 2018: AAC-00091.
Search in Google Scholar Back to article
Resende CA, Figueiredo AM. Discrimination of methicillin-resistant Staphylococcus aureus from borderline-resistant and susceptible isolates by different methods. J Med Microbiol. 1997; 46:145–9.
Search in Google Scholar Back to article
Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing. [online] 2017. [cited 2018 Jan 11]. Available from: https://clsi.org/media/1469/m100s27_sample.pdf
Search in Google Scholar Back to article
National Committee for Clinical Laboratory Standards. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. 4th ed. vol. 17, no. 2. Wayne, PA: National Committee for Clinical Laboratory Standards document M7-A4; 1997.
Search in Google Scholar Back to article
Shrestha B, Pokhrel BM, Mohapatra TM. Phenotypic characterization of nosocomial isolates of Staphylococcus aureus with reference to MRSA. J Infect Dev Countries. 2009; 3:554–60.
Search in Google Scholar Back to article
National Committee for Clinical Laboratory Standards. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. Wayne, PA: National Committee for Clinical Laboratory Standards document M07-A9; 2012.
Search in Google Scholar Back to article
National Committee for Clinical Laboratory Standards. Performance standards for antimicrobial susceptibility testing: twenty third informational supplement edition. Wayne, PA: National Committee for Clinical Laboratory Standards document M100-S23; 2013.
Search in Google Scholar Back to article
Swenson JM, Spargo J, Tenover FC, Ferraro MJ. Optimal inoculation methods and quality control for the NCCLS oxacillin agar screen test for detection of oxacillin resistance in Staphylococcus aureus. J Clin Microbiol. 2001; 39:3781–4.
Search in Google Scholar Back to article
Bidya S, Suman RS. Comparative study of three β lactamase test methods in Staphylococcus aureus isolated from two Nepalese hospitals. Open J Clin Diagn. 2014; 4:47.
Search in Google Scholar Back to article
Sambrook JF, Russell DW, editors. Molecular cloning: a laboratory manual, vol. 1, 2, 3. New York: Cold Spring Harbor Laboratory Press; 2001.
Search in Google Scholar Back to article
Prasad S, Nayak N, Satpathy G, Nag HL, Venkatesh P, Ramakrishnan S, et al. Molecular and phenotypic characterization of Staphylococcus epidermidis in implant related infections. Indian J Med Res. 2012; 136:483.
Search in Google Scholar Back to article
García-Álvarez L, Holden MT, Lindsay H, Webb CR, Brown DF, Curran MD, et al. Methicillin-resistant Staphylococcus aureus with a novel mecA homologue in human and bovine populations in the UK and Denmark: a descriptive study. Lancet Infect Dis. 2011; 11:595–603.
Search in Google Scholar Back to article
Khairalla AS, Wasfi R, Ashour HM. Carriage frequency, phenotypic, and genotypic characteristics of methicillin-resistant Staphylococcus aureus isolated from dental health-care personnel, patients, and environment. Sci Rep. 2017; 7:7390.
Search in Google Scholar Back to article
Gebhardt DO. MRSA in the Netherlands: preventive measure raises a moral issue. J Med Ethics. 2003; 29:212.
Search in Google Scholar Back to article
Khorvash F, Mostafavizadeh K, Mobasherizadeh S. Frequency of mecA gene and borderline oxacillin resistant Staphylococcus aureus in nosocomial acquired methicillin resistance Staphylococcus aureus infections. Pak J Biol Sci. 2008; 11:1282–5.
Search in Google Scholar Back to article
Hryniewicz MM, Garbacz K. Borderline oxacillin-resistant Staphylococcus aureus (BORSA) – a more common problem than expected? J Med Microbiol. 2017; 66:1367–73.
Search in Google Scholar Back to article
Huang YT, Liao CH, Chen SY, Hsu HS, Teng LJ, Hsueh PR. Emergence of multidrug-resistant sequence type 45 strains among mecA-positive borderline oxacillin-resistant Staphylococcus aureus causing bacteraemia in a medical centre in Taiwan. Int J Antimicrob Agents. 2018; 52:70–5.
Search in Google Scholar Back to article
Sasirekha B, Usha MS, Amruta AJ, Ankit S, Brinda N, Divya R. Evaluation and comparison of different phenotypic tests to detect methicillin resistant Staphylococcus aureus and their biofilm production. Int J Pharm Tech Res. 2012; 4:532–41.
Search in Google Scholar Back to article
Bonjean M, Hodille E, Dumitrescu O, Dupieux C, Mongo CN, Allam C, et al. Disk diffusion testing for detection of methicillin-resistant Staphylococci: does moxalactam improve upon cefoxitin? J Clin Microbiol. 2016; 54:2905–9.
Search in Google Scholar Back to article
Basset P, Prod’hom G, Senn L, Greub G, Blanc DS. Very low prevalence of methicillin-resistant Staphylococcus aureus carrying the mecC gene in western Switzerland. J Hosp Infect. 2013; 83:257–9.
Search in Google Scholar Back to article
Adhikari R, Pant ND, Neupane S, Neupane M, Bhattarai R, Bhatta S, et al. Detection of methicillin resistant Staphylococcus aureus and determination of minimum inhibitory concentration of vancomycin for Staphylococcus aureus isolated from pus/wound swab samples of the patients attending a tertiary care Hospital in Kathmandu, Nepal. Canadian Can J Infect Dis Med Microbiol. 2017; 2017:2191532.
Search in Google Scholar Back to article
Kaase M, Lenga S, Friedrich S, Szabados F, Sakinc T, Kleine B, Gatermann SG. Comparison of phenotypic methods for penicillinase detection in Staphylococcus aureus. Clin Microbiol Infect. 2008; 14:614–6.
Search in Google Scholar Back to article
Kogan S, Zeng Q, Ash N, Greenes RA. Problems and challenges in patient information retrieval: a descriptive study. Proc AMIA Symp. 2001: 329–33.
Search in Google Scholar Back to article
San Sit P, Teh CS, Idris N, Sam IC, Omar SF, Sulaiman H, et al. Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection and the molecular characteristics of MRSA bacteraemia over a two-year period in a tertiary teaching hospital in Malaysia. BMC Infect Dis. 2017; 17:274.
Search in Google Scholar Back to article