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ORIGINAL ARTICLE
Year : 2019  |  Volume : 12  |  Issue : 1  |  Page : 39-43  

Surveillance of health-care workers for nasal carriage to detect multidrug-resistant Staphylococcus spp. in a tertiary care center: An observational study


1 Department of Microbiology, Hind Institute of Medical Science, Lucknow, Uttar Pradesh, India
2 Department of Emergency Medicine, SGPGI, Lucknow, Uttar Pradesh, India
3 Department of Microbiology, KGMU, Lucknow, Uttar Pradesh, India
4 Department of Microbiology, Era's Medical College, Lucknow, Uttar Pradesh, India
5 Department of Microbiology, RMLIMS, Lucknow, Uttar Pradesh, India

Date of Submission03-May-2018
Date of Acceptance24-Jul-2018
Date of Web Publication22-Jan-2019

Correspondence Address:
Tanmoy Ghatak
Rammohan Pally, Arambagh, Hooghly - 712 601, West Bengal
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mjdrdypu.mjdrdypu_74_18

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  Abstract 


Background: Healthcare-associated infection (HCAI) has become a potential risk worldwide. Staphylococcus spp., especially methicillin-resistant Staphylococcus aureus (MRSA) is one of the frequent causes of HCAIs. Coagulase-negative Staphylococcus (CoNS), previously considered as contaminants, now emerged as opportunist nosocomial pathogens for causing HCAIs such as bloodstream infections. Health-care workers (HCWs) play a role in colonizing and transmit microorganism to patient causing HCAIs. The purpose of this study was for surveillance of MRSA and MR-CoNS as nasal colonizer among HCWs and its antimicrobial susceptibility pattern. Materials and Methods: Nasal swabs were collected from 214 HCWs such as doctor, nurse, sweepers, ward boy, and operation theatre (OT) assistant working in Intensive Care Unit and OT and ward. Methicillin resistance among the Staphylococcus spp. isolates were detected using cefoxitin 30 μg disc. Antimicrobial susceptibility profile of the Staphylococcus spp. isolates were also determined for several other antibiotics. Results: Of 214 nasal swabs collected from HCWs, 97.6% of doctors, 93.2% of nurses, and 94.6% of sweepers showed growth of Staphylococcus spp. MRSA was 13%, 6.7%, and 14.2% in samples obtained from anterior nares of doctors, nurses, and sweepers, respectively. MR-CoNS were 41.6%, 32.4%, and 32.1% in samples obtained from anterior nares of doctors, nurses, and sweepers, respectively. Conclusion: Multidrug-resistance Staphylococcus spp. carriage is very high among HCWs in our tertiary care center. Our study created awareness among HCWs by educating them about nasal carriage of MDR organisms.

Keywords: Health-care workers, multidrug resistance, nasal carriage, Staphylococcus spp


How to cite this article:
Kulshrestha N, Ghatak T, Gupta P, Singh M, Agarwal J. Surveillance of health-care workers for nasal carriage to detect multidrug-resistant Staphylococcus spp. in a tertiary care center: An observational study. Med J DY Patil Vidyapeeth 2019;12:39-43

How to cite this URL:
Kulshrestha N, Ghatak T, Gupta P, Singh M, Agarwal J. Surveillance of health-care workers for nasal carriage to detect multidrug-resistant Staphylococcus spp. in a tertiary care center: An observational study. Med J DY Patil Vidyapeeth [serial online] 2019 [cited 2019 Apr 25];12:39-43. Available from: http://www.mjdrdypv.org/text.asp?2019/12/1/39/250447




  Introduction Top


Healthcare-associated infection (HCAI) has become a potential threat worldwide. HCAIs can cause increased morbidity and mortality of the patients and increase treatment cost, especially in developing country like ours.[1],[2] Moreover, with the advent of multidrug-resistant (MDR) bacteria, HCAIs are now very difficult to treat. Cross-transmission of infections in between patients by health-care workers (HCWs) also plays a role.[3]

Staphylococcus spp., especially, methicillin-resistant Staphylococcus aureus (MRSA) is one of the frequent causes of HCAIs.[4] S. aureus colonizes various places and mucous membrane of the human body, mostly at anterior nares.[5] This way a healthy human become a carrier of S. aureus. The colonized HCWs can act as carrier as well as reservoir of S. aureus. They become major sources of S. aureus transmission between patients. Especially, vulnerable patients in the operation theater (OT), Intensive Care Unit (ICU), and postoperative wards are susceptible for spread of microbial resistance from HCWs.

Coagulase-negative Staphylococci (CoNS) were previously considered as contaminants. They now emerge as opportunist nosocomial pathogens for hospitalized patients. CoNS are causing several HCAIs including bloodstream infection.[6] CoNS are similarly colonized in different parts of the skin and mucous membranes of the HCWs.[7] Methicillin resistance becomes common to CoNS causing difficulties in treatment policies.[8]

The MRSA carrier stage and rate among HCWs are much talked about. It ranges from 16.8%–90% in different countries.[9],[10] However, carrier stage, colonization of MR-CoNS among HCWs is poorly reported.

This study is therefore undertaken as part of a hospital infection control surveillance program of our tertiary care center. Because nasal carriage of MDR bacteria among HCWs has become a significant issue, it demands further study/investigation.


  Materials and Methods Top


Institutional ethical committee clearance was taken for this surveillance study. Written and informed consent was taken from each HCW participating in the study. The sample size of the study was planned using the “sample size determination in health studies software” of the World Health Organization (WHO).[11]

Specimen collection

Specimens were taken from anterior nares of HCWs (doctors, nurses, sweepers, ward boy, and OT assistant) working in ICU and OT and ward.

Exclusion criteria

Staffs having rhinorrhea/rhinitis, pharyngitis, upper respiratory tract infection, and who were on oral antibiotics were excluded from the study.

Procedure of anterior nasal swab

With gloved hands, sterile cotton wool swab stick with plastic transport tube was taken and swab was removed. Swab was premoistened with nonbacteriostatic normal saline. HCW was asked to tilt the head back and swab was gently inserted into the nostril and rotated against the anterior nasal mucosa for 3 s. Using the same swab, the procedure was repeated for other nostril and placed into plastic transport tube. Plastic transport tube was labeled with appropriate information.

These swabs were inoculated on the 5% sheep blood agar and mannitol salt agar without delay. Colony characteristics on the culture plates and Gram-staining were used to further confirm the identity of S. aureus. Salt tolerance and mannitol fermentation properties of S. aureus result in the typical yellow colonies due to a change in the pH. Gram staining helped to ascertain that there were no other airborne contaminants by confirming the characteristic morphology of S. aureus. Catalase, dimethyl sulfoxide oxidase, deoxyribonuclease, and coagulase tests helped to identify species of S. aureus. Growth of any other microorganisms was noted but excluded from analysis.

Antibiogram was made by the Kirby–Bauer Disc Diffusion Method as per the Clinical and Laboratory Standards Institute Standards.[12] The zone diameters were interpreted against the following antibiotics – penicillin G (10 units), ampicillin (10 mcg), erythromycin (15 mcg), tetracycline (30 mcg), gentamicin (10 mcg), vancomycin (30 mcg), co-trimoxazole (1.25/23.75 mcg), ciprofloxacin (10 mcg), linezolid (30 mcg), and imipenem (10 mcg). Methicillin resistance was detected using cefoxitin 30 μg disc (HiMedia Labs, India). Zone of inhibition of size <21 mm for S. aureus and <24 mm for CoNS was considered as resistant.[13] Information on MRSA and MR-CoNS was disseminated in health education sessions to complement the findings of the study.


  Results Top


A total of 240 HCWs were targeted. Nine HCWs were excluded due to rhinitis and respiratory tract infection, 2 HCWs were on oral antibiotics, 7 negatively consented, and 8 samples were discarded due to plate contamination. 214 samples from anterior nares were analyzed from ICU, OT, and wards. 84 samples from doctors' anterior nares, 74 samples from nurses' anterior nares, and 56 samples from sweepers and ward boys' anterior nares working in ICU, OT, and wards were collected.

Among 84 anterior nares samples of doctors, 97.6% showed growth of Staphylococcus spp. Of them, 11 (13%) were MRSA and 35 (41.6%) were MR-CoNS MRSA was 7%, 23%, and 15% from anterior nares of doctors posted in ICU, OT, and ward, respectively. MR-CoNS was 43%, 31%, and 41% from anterior nares of doctors posted in ICU, OT, and ward, respectively [Table 1].
Table 1: Culture of anterior nares of doctors, nurses, and sweepers (n=214)

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Among 74 anterior nares samples of nurses, 93.2% showed growth of Staphylococcus spp. Of them, 5 (6.7%) were MRSA and 24 (32.4%) were MR-CoNS. There are no MRSA found in anterior nares samples of ward nurses. MRSA was 4%, 13%, and 0% and MR-CoNS was 55%, 27%, and 12% from anterior nares of nurses posted in ICU, OT, and ward respectively [Table 1].

Among 56 anterior nares samples of sweepers, 94.6% showed growth of Staphylococcus spp. Of them, 8 (14.2%) were MRSA and 18 (32.1%) were MR-CoNS. MRSA was 10%, 11%, and 23% and MR-CoNS was 37%, 26%, and 35% from anterior nares of sweepers and ward boys posted in ICU, OT, and ward, respectively [Table 1]. MRSA was 13%, 6.7%, and 14.2% in samples obtained from anterior nares of doctors, nurses, and sweepers, respectively. MR-CoNS were 41.6%, 32.4%, and 32.1% in samples obtained from anterior nares of doctors, nurses, and sweepers, respectively. There is no statistical difference of MRSA and MR-CoNS nasal carriage in between groups.

Antibiogram of multidrug-resistant organisms

Of all MRSA found in anterior nares of doctors, 72.7% of MRSA were also macrolide resistant. Of 72.7% of macrolide resistance, 10% is inducible resistance. Of all MRSA found in anterior nares of nurses, 60% of MRSA were also macrolide resistant. Of 60% of macrolide resistance, all are constitutive resistant. MRSA found in anterior nares of sweepers, 62.5% of were also macrolide resistant. Of 62.5% of MR, 11% is inducible resistance [Table 2].
Table 2: Antibiogram of methicillin-resistant Staphylococcus aureus found in doctors' nares

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Antibiogram of methicillin-resistant coagulase -negative Staphylococcus found in nares

Of all MR-CoNS found in anterior nares of doctors, 54.2% was also macrolide resistant, 2.8% were also macrolide and linezolid resistant, and 2.8% were also macrolide and levofloxacin resistant. Of 54.2% of macrolide resistant, 10% is inducible resistance [Table 3].
Table 3: Antibiogram of methicillin-resistant coagulase-negative Staphylococcus found in nares

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Of all MR-CoNS found in anterior nares of nurses, 66.6% were also macrolide resistant. Of 66.6% of macrolide-resistant MR-CONS, all are constitutively resistant [Table 3].

Of all MR-CoNS found in anterior nares of sweepers, 50% were also macrolide resistant and 5.5% were also macrolide and levofloxacin resistant. Of 50% of MR, 11% is inducible resistance [Table 3].


  Discussion Top


Healthcare-associated infections are of major public health importance worldwide. They can occur in all health-care settings with an estimated 3.5%–12% of hospitalized patients affected in developing countries (WHO, 2011).[14] The presence of MDR bacteria, especially S. aureus on hands with healthy skin usually represents contamination because these bacteria rarely multiply and persist at this site. Nasal carriage of MDR bacteria was a risk factor for carrying them on the hands. The mechanism probably involves self-inoculation by fingers touching the nose.[15]

In this study, it was found that (212) 99% of the HCWs had colonization in their nose. There was a high carriage rate of Staphylococcus spp. in anterior nares (204) 95.3% of HCWs.

Doctors were found to carry Staphylococcus spp. in 97.6% of anterior nares samples (n = 84). The most predominant MDR organism found to colonize them were MR-CoNS and MRSA. Of these, 13% were MRSA and 41.6% were MR-CoNS.

Nurses and sweepers were found to carry Staphylococcus spp. in 93.2% (n = 76) and 94.6% (n = 56) of anterior nares sample, respectively. Of these, the most predominant MDR organism found to colonize were MR-CoNS and MRSA. Nurses had 6.7%MRSA and 32.4% MR-CoNS in their anterior nares. Similarly, sweepers had 14.2% MRSA and 32.1% MR-CoNS in anterior nares.

Anterior nares of doctors and sweepers were found to be more commonly colonized with MDR Staphylococcus spp. in comparison to nurses. This problem in resident doctors could be because of long duty hours, heavy workload, poor hygiene, and sometimes reluctance to practice hand hygiene. Similar problem in sweepers could be because of unawareness of infection control practices among them.

A recent screening study of nasal carriage of S. aureus by staff members was carried out at a public hospital in Argentina, 2017. Of the 320 HCWs, they found 96 (30%) were nasal carriers of S. aureus, 6.3% (20) of whom carried MRSA. MRSA was widely resistant to macrolides, quinolones, and however, were sensitive to sulfamethoxazole-trimethoprim or vancomycin.[1] Our study showed that the nasal carriage of S. aureus as well as MRSA was higher among HCWs. The resistance patterns of S. aureus were also different. The difference between study outcomes in Argentina and study like ours may be attributed to the strict infection control practices that are followed over there and also to the better doctor to population ratio.

In an Indian study done in tertiary care center in Assam 2013, Rongpharpi et al. sampled 315 nasal swabs.[14] In their study, they isolated nasal carriage of S. aureus in 22.22% (70) cases. Methicillin resistance was seen in 11.43% (8) of the S. aureus isolates. Nasal carriage of CoNS was 42.86% (135) in their study, but they have not disclosed percentage of MR-CoNS. The prevalence of S. aureus was higher among the male HCWs (54.28%) than the female HCWs (45.71%). All the S. aureus isolates were found to be sensitive to vancomycin and linezolid. Our study showed higher MRSA nasal carriage among HCWs.

In 2011, Kumar et al. did nasal swab of 84 HCWs of ward, OT, and ICU in Aligarh, India. 78.6% were positive for S. aureus. The nasal carriage of MRSA was observed to be 83.3% (15) among doctors and 16.6% (3) among laboratory technicians.[16] Nasal carriage of CoNS was 39.3% (26). In our study, 13% of doctors had nasal carriage of MRSA, while 6.7% and 14.2% of nurses and sweepers had nasal carriage of MRSA, respectively.

In 2013, Edem et al. designed a study to ascertain the frequency of bacterial colonization and the antibiotic sensitivity pattern of the isolates from the anterior nares of HCWs in a teaching hospital, Nigeria. They analyzed 30 nasal samples and their study revealed that 93% of HCWs carry Staphylococcus spp. in their nostrils and 20% (6) showed MRSA colonization in their noses. Staphylococcus spp. were found to be sensitive to clindamycin (80%), followed by ciprofloxacin (77%).[4]

An Indian study of 2016 described methicillin- and mupirocin-resistant MR-CoNS from nasal swabs collected from various categories of 210 HCWs in equal representation.[17] Of 210 swabs, 69 (32.8%) were CoNS and 16 (7.6%) were MR-CoNS isolates. Their MR-CoNS strains showed resistance against antibiotics such as penicillin (100%), rifampin (88%), clindamycin (69%), co-trimoxazole (63%), and erythromycin (56%). Our study showed higher rates of MR-CoNS carriage, 41.6% among doctors and 32.4% and 32.1% among nurses and word boys, respectively.


  Conclusion Top


The study showed that the HCWs including doctors, nurses, OT assistant, sweepers, and ward boys were carrier for MDR organisms such as MRSA and MR-CoNS. Our study created awareness among HCWs by educating them about nasal MDR organism carriage, especially MRSA and MR-CoNS and different measures to eradicate it. Our study gives an overview of the nature of MRSA and MR-CoNS isolates in this portion of India for epidemiologists. Our tertiary care hospital, however, needs to develop more stringent hospital infection control policies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Rajaduraipandi K, Mani KR, Panneerselvam K, Mani M, Bhaskar M, Manikandan P, et al. Prevalence and antimicrobial susceptibility pattern of methicillin-resistant Staphylococcus aureus: A multicentre study. Indian J Med Microbiol 2006;24:34-8.  Back to cited text no. 2
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Edem EN, Onwuezobe IA, Ochang EA, Etok CA, James IS. Antibiogram of bacterial isolates from the anterior nares and hands of health care workers in university of Uyo teaching hospital (UUTH) Uyo, AkwaIbom state, Nigeria. J Bacteriol Parasitol 2013;4:168.  Back to cited text no. 4
    
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Lwanga SK, Lemeshow S. Sample Size Determination in Health Studies: A Practical Manual. Geneva, Switzerland: World Health Organization; 1991.  Back to cited text no. 11
    
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Bauer AW, Perry DM, Kirby WM. Single-disk antibiotic-sensitivity testing of Staphylococci; an analysis of technique and results. AMA Arch Intern Med 1959;104:208-16.  Back to cited text no. 12
    
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Clinical and Laboratory Standards Institute. Approved standard: M02-A10. Performance Standards for Antimicrobial Disk Susceptibility Tests. 10th ed. Wayne, PA: Clinical and Laboratory Standards Institute; 2009.  Back to cited text no. 13
    
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Rongpharpi SR, Hazarika NK, Kalita H. The prevalence of nasal carriage of Staphylococcus aureus among healthcare workers at a tertiary care hospital in Assam with special reference to MRSA. J Clin Diagn Res 2013;7:257-60.  Back to cited text no. 15
    
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Agarwal L, Singh AK, Agarwal A, Agarwal A. Methicillin and mupirocin resistance in nasal colonizers coagulase negative Staphylococcus among health care workers. Med J DY Patil Univ 2016;9:479-83.  Back to cited text no. 17
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  [Table 1], [Table 2], [Table 3]



 

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