Shakthi R and Venkatesha D: MRSA colonization in health care professionals with varying degrees of exposure to the hospital environment and its susceptibility to mupirocin in a tertiary care centre


Introduction

Staphylococcus aureus is the most important cause of wound and skin infections. It is one of the common pathogen colonizing the hospital environment. Occurrence of resistance to semi synthetic penicillinase resistant penicillines such as Oxacillin and Methicillin is noted. Resistance is due to presence of an altered penicillin binding protein called PBP2a or PBPs from chromosomal gene called mecA. The S.aures strains with mecA determinant are termed as Methicillin resistant Staphylococcus aureus (MRSA).1 Methicillin resistance is usually acquired during exposure to hospitals and other health care facilities.2 MRSA can colonize the nose and other skin sites without causing infection. It can spread by the colonized hands of health care workers (HCWs). Colonized HCWs and students may develop infections and act as reservoirs for infection among vulnerable patients.3 Identification of HCWs colonized with MRSA followed by implementation of standard MRSA decolonization therapy such as topical application of 2% Mupirocin, chlorhexidine glucoanate, bacitracin along with oral therapies with tetracycline, folate inhibitors etc. have shown effective in reducing the transmission and controlling the spread of MRSA.4

Decontamination of MRSA carriers by 2% Mupirocin can decrease the infection rate among patients. However, inappropriate over the counter use, treatment of wounds, pressure sores and routine use in peritoneal dialysis with Mupirocin are associated with resistance, which will be a major setback for future use of Mupirocin.5 Mupirocin susceptibility is categorised into three types:

  1. Mupirocin susceptible with minimum inhibitory concentration (MIC) of <4 μg/ml(Mup S)

  2. Low-level Mupirocin resistance (Mup RL) with MIC of >8–256 μg/ml

  3. High-level Mupirocin resistance (Mup RH) with MIC of >512 μg/ml.

The resistance can be detected by Kirby–Bauer disc diffusion method, but dilution method is considered the gold standard for the determination of Mupirocin resistance levels.6, 7

The present study was undertaken to screen HCWs with varying degree of exposure to hospital environment and to know the susceptibility of Mupirocin in this group.

Material and Methods

This cross-sectional study was done in department of Microbiology, Adichunchanagiri Institute of Medical sciences, B.G.Nagara. The study period was from July 2019 to December 2019. The ethical committee approval was taken. The samples were collected after taking written consent from all participants.

Inclusion criteria

  1. HCWs (working in OPD, wards and ICU were included in the study group.

Exclusion criteria

Persons with prior MRSA colonization, Coagulase Negative Staphylococcus aureus (CONS), Methicillin resistance Coagulase Negative Staphylococcus aureus (MRCONS) were excluded from the study.

Nasal swabs from anterior nares and inter digital space samples were collected using sterile cotton swabs. The tip of the nasal swab was inserted approximately 1 inch into the nares and rolled five times in each nostril. The specimens were inoculated onto blood agar within 1 hour of collection and incubated overnight at 37⁰C. Suspected colonies of S.aureus were confirmed by morphology, Gram’s stain, Catalase test; Slide and tube coagulase test, Mannitol salt agar, DNAse agar.8

Antibiotic susceptibility to Methicillin was assessed using Kirby-Bauer disc diffusion method using Cefoxitin disc (30µg) as per CLSI guidelines. The Staphylococcus aureus with Zone of diameter of ˂21mm were considered as MRSA.9 Repeat samples were collected from the participants with nasal carriage of MRSA after completion of 2% Mupirocin topical application for 7 days and they were processed in the same manner as mentioned above for the confirmation of effective decontamination.

The MRSA isolates were then tested for Mupirocin Susceptibility by Kirby-Bauer disc diffusion method using 5µg and 200µg Mupirocin disc (HiMedia Laboratories pvt Ltd, Mumbai, India) to determine low and high level resistance The zone diameters were carefully examined with transmitted light for any light growth within the zone of inhibition. Isolates with no zone of inhibition were interpreted as Mupirocin resistant. Isolate resistant to 5μg disc and any zone for 200μg disc was considered MupRL. Isolates resistant for both the discs were MupRH.7, 9, 10

Statistical analysis was done using Microsoft Excel. All the data statistically analyzed using Chi-square test to calculate significant levels. P < 0.05 was considered statistically significant

Result

Among 100 HCWs screened, 69 were nursing staffs, 10 doctors and 21 post graduate students.

Out of 100 Nasal swabs from HCWS, 30 yielded S.aureus of which 15 were MRSA. (Table 1) Out of 69 nasal swabs from nursing staffs 28 were S.aureus, with 4 MRSA strains. Out of 10 doctors 3 were S.aureus, with 3 MRSA strains and out of 21 Post graduate students 9 were S.aureus with 3 MRSA strains. (Table 2)

Out of 100 inter digital spaces swabs 22 yielded S.aureus of which 10 were MRSA strains and 30 contaminants. Out of 69 swabs from nursing staffs 14 were S.aureus, with 8 MRSA strains. Out of 10 doctors 2 were S.aureus, with 1 MRSA strain and out of 21 Post graduate students 6 were S.aureus with 1 MRSA strain. (Table 3)

In the present study, 100 nasal and inter digital spaces swabs yielded 15 and 10 MRSA strains respectively. (Figure 1)

Among the 100 HCWs screened, the majority of MRSA colonization was seen in HCWs with a history of exposure to hospital environment for around 5-10 years or more (Figure 2).

All 30 S.aureus with 15 MRSA strains isolated were sensitive to both 5µg and 200µg Mupirocin disc by Kirby-Bauer disc diffusion method.

All the MRSA colonized HCWs and students were given 2% Mupirocin nasal ointment with Chlorhexidine body wash / soap for 5 days and the samples recollected at 7th day were Negative for MRSA.

Table 1

Isolation of S. aureus from Nasal and Inter digital space swab

Total swabs

S.aureus

MRSA

Contaminants

Nasal

100

30

15

-

Inter digital spaces

100

22

10

30

Table 2

Isolation pattern of S. aureus from Nasal swabs among Health care workers

HCW

Total swabs

S.aureus

MRSA

Doctors

10

2

3

Post graduate students

21

6

4

Staff nurses

69

22

8

Total

100

30

15

Table 3

Isolation pattern of S. aureus from Inter digital space swab among Health care workers

HCW

Total swabs

S.aureus

MRSA

Doctors

10

2

1

Post graduate students

21

6

1

Staff nurses

69

14

8

Total

100

22

10

Table 4

Comparison of the MRSA colonization rates in Health care workers from different studies

S. No.

Author’s Name

MRSA colonization among HCWs (%)

1

The present study

15

2

Kakhandki LS et al11

12.10

3

Golia et al al12

13.37

4

Rongpharpi et al13

11.43

5

Al Lahman et al14

22.6

6

Archana Iyer et al15

76

Figure 1

MRSA isolated from Nasal and inter-digital swabs

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/648428c4-96ee-4e29-a774-e11e9d80a0b4/image/5afcb08a-23f5-4519-a4e7-c865312c65ae-uimage.png

Figure 2

MRSA colonization in HCWs based on years of exposure to the hospital environment

https://typeset-prod-media-server.s3.amazonaws.com/article_uploads/648428c4-96ee-4e29-a774-e11e9d80a0b4/image/fd42d4f5-0887-4c86-90f0-44630766e721-uimage.png

Discussion

MRSA colonization increases the risk of infection with MRSA in both early and long term carriers of which 23% develop MRSA infection the following year.16 Increasing colonization of MRSA nasal carriage among HCWs leads to increased infection in both community and hospital. These individuals act as a potential source of infection especially to their immunocompromised patients, resulting in prolonged hospital stay and health care expenditure.17

Detection of MRSA colonization among HCWs in hospital is necessary especially for those working in the critical care areas.

In our study, the overall nasal carriage rate of S. aureus and MRSA was 30% and 15% respectively. Our results are in comparable to those of a recent studies by Kakhandki LS et al., Golia et al., Rongpharpi et al. and Al Lahman et al.,11, 12, 13, 14 whereas a very high rate of MRSA colonization has been reported by Archana Iyer et al., in Saudi Arabia.15(Table 4)   

In the present study, MRSA colonization rate among doctors, post graduate students and nursing staffs are found to be 3 %, 4% and 8% respectively, indicating no significant difference between the carriage rates of MRSA among doctors and Nursing staffs. These findings are similar to other studies.18, 19, 20

Among the 100 HCWs screened, the majority of MRSA colonization was seen in HCWs with a history of exposure to hospital environment for around 5-10 years. This high rate of colonization could be due to their active involvement in hospital work, continuous patient contact. In a study by Askarian M et al., there was no significant differences in the colonization rates between individuals with varying degree of exposure to hospital.21

All 30 S.aureus with 15 MRSA strains isolated were sensitive to both 5µg and 200µg Mupirocin, However, most of the studies related to clinical isolates and its susceptibility to Mupirocin showed both high level and low levels of Mupirocin resistance.22, 23, 24

The high rate of MRSA colonization among HCWs is potential source of infection for the patients who receive care from them, causing nosocomial infections. Hence regular screening of the HCWs for MRSA colonization and taking the appropriate preventive measures helps in significant decrease in mortality and morbidity. The prevalence of MRSA may vary between institutions, geographic areas, study design, sample size and method employed for MRSA detection.25 The limitation of this study was relatively small sample size and an increase in sample size could have yielded statistically significant results.

Conclusion

All HCWs should be screened for MRSA colonization, which provide an early warning of the presence of Multidrug resistant pathogens. The high rate of Nasal MRSA carriage among health care workers is alarming. Health care professionals with long duration of exposure to hospital environment were more colonized with MRSA. Proper measures must be implemented to control the spread of MRSA such as laboratory based surveillance, isolation of colonized persons, proper hand hygiene practices and proper decontamination measures for carriers. The detection of susceptibility of Mupirocin will result in appropriate use of this antibiotic in decolonization.

Source of Funding

None.

Conflict of Interest

The authors declare that there is no conflict of interest.

.

References

1 

W Winn Gram positive cocci. Staphylococci and related gram positive cocciKoneman's Color Atlas and Textbook of Diagnostic Microbiology6th editionLippincott Williams and WilkinsBaltimore200662437

2 

P Datta N Gulati N Singla HR Vasdeva K Bala J Chander Evaluation of various methods for the detection of meticillin-resistant Staphylococcus aureus strains and susceptibility patternsJ Med Microbiol201160111613610.1099/jmm.0.032219-0

3 

HFL Wertheim DC Melles MC Vos W van Leeuwen A van Belkum HA Verbrugh The role of nasal carriage in Staphylococcus aureus infectionsLancet Infect Dis20055127516210.1016/s1473-3099(05)70295-4

4 

CL Abad MS Pulia N Safdar Does the Nose Know? An Update on MRSA Decolonization StrategiesCurr Infect Dis Rep20131564556410.1007/s11908-013-0364-y

5 

JB Patel RJ Gorwitz JA Jernigan Mupirocin resistance. Antimicrobial resistanceClin Infect Dis20094993541

6 

DJ Hetem MJM Bonten Clinical relevance of mupirocin resistance in Staphylococcus aureusJ Hosp Infect20138542495610.1016/j.jhin.2013.09.006

7 

V Shivanna RN Kumar D Venkatesha The emergence of Mupirocin resistance among the clinical isolates of Staphylococci in a rural tertiary health-care centre of South IndiaJ Acad Clin Microbiol201820114810.4103/jacm.jacm_18_17

8 

CLSI. Performance Standards for Antimicrobial Susceptibility Testing. CLSI Approved Standard M100 S23. Wayne, PA: Clinical and Laboratory Standards Institute2013Wayne, PA

9 

JE Finlay LA Miller JA Poupard Interpretive criteria for testing susceptibility of staphylococci to mupirocin.Antimicrob Agents Chemother19974151137910.1128/aac.41.5.1137

10 

M100-S25. Screening Test for Detection of High-Level Mupirocin Resistance in Staphylococcus aureus: 24th Informational SupplementCLSIWayne, PA2015

11 

A Iyer T Kumosani E Azhar E Barbour S Harakeh High incidence rate of methicillin-resistant Staphylococcus aureus (MRSA) among healthcare workers in Saudi ArabiaJ Infect Dev Ctries2014803372810.3855/jidc.3589

12 

LS Kakhandki BV Peerapur Study of nasal carriage of MRSA among the clinical staff and health care workers of a teaching hospital of Karnataka, IndiaAl Ameen J Med Sci20125436770

13 

S Golia V Hittinahalli AS Kamath AR Nirmala A study of nasal carriage of MRSA among the health care workers of a tertiary care hospitalInt J Basic Appl Med Sci201333

14 

Sharon Rainy Rongpharpi The Prevalence of Nasal Carriage of Staphylococcus Aureus Among Healthcare Workers at a Tertiary Care Hospital in Assam with Special Reference to MRSAJ Clin Diagn Res201372576010.7860/jcdr/2013/4320.2741

15 

N Al Laham Detection and antibiotic resistance pattern of Staphylococcus aureusand (MRSA) isolated from healthcare workers Nares at three Gaza hospitals, PalestineInt Arabic J Antimicrob Agents201610.3823/779

16 

R Datta SS Huang Risk of Infection and Death due to Methicillin‐ResistantStaphylococcus aureusin Long‐Term CarriersClin Infect Dis20084721768110.1086/589241

17 

J Malini AH Shruti M Padmavathy BL Umapathy BV Navaneeth JK Mannan Methicillin-resistant Staphylococcus aureus carriage among the health care workers in a tertiary care hospitalJCDR2012657913

18 

WC Albrich S Harbarth Health care workers: source, vector or victim of MRSALancet Infect Dis20088289301

19 

B Shrestha BM Pokhrel TM Mohapatra Staphylococcus aureus nasal carriage among health care workers in a Nepal HospitalBraz J Infect Dis200913532210.1590/s1413-86702009000500001

20 

A Shibabaw T Abebe A Mihret Nasal carriage rate of methicillin resistant Staphylococcus aureus among Dessie Referral Hospital Health Care Workers; Dessie, Northeast EthiopiaAntimicrob Resist Infect Control2013212510.1186/2047-2994-2-25

21 

M Askarian A Zeinalzadeh A Japoni A Alborzi ZA Memish Prevalence of nasal carriage of methicillin-resistant Staphylococcus aureus and its antibiotic susceptibility pattern in healthcare workers at Namazi Hospital, Shiraz, IranInt J Infect Dis2009135e241710.1016/j.ijid.2008.11.026

22 

AK Singh AK Singh S Shukla L Agarwal Parul Chaturvedi Prevalence of mupirocin resistant Staphylococcus aureus isolates among patients admitted to a tertiary care hospitalNorth Am J Med Sci201468403710.4103/1947-2714.139293

23 

SK Oommen B Appalaraju K Jinsha Mupirocin resistance in clinical isolates of staphylococci in a tertiary care centre in south IndiaIndian J Med Microbiol2010284372510.4103/0255-0857.71825

24 

AK Singh V Venkatesh M Singh Mupirocin resistance in clinical isolates ofStaphylococcus aureusin a tertiary care hospital set up in North IndiaInt J Med Res Health Sci201324840710.5958/j.2319-5886.2.4.134

25 

S Pavani DS Murthy Prevalence of colonization of MRSA in Health care workers the compliance to hand hygiene a need of the hourSch J App Med Sci201646E22036



jats-html.xsl

© This is an open access article distributed under the terms of the Creative Commons Attribution License Attribution 4.0 International (CC BY 4.0). which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


  • Article highlights
  • Article tables
  • Article images

Article History

Received : 23-02-2021

Accepted : 12-03-2021

Available online : 02-04-2021


View Article

PDF File   Full Text Article


Copyright permission

Get article permission for commercial use

Downlaod

PDF File   XML File   ePub File


Digital Object Identifier (DOI)

Article DOI

https://doi.org/10.18231/j.ijmr.2021.015


Article Metrics






Article Access statistics

Viewed: 294

PDF Downloaded: 119