Comparative Study of Prevalence of MRSA on Surfaces of Different Laboratories in Bangalore in the COVID-19 Era

Introduction

Staphylococcus aureus is an opportunistic pathogen often carried asymptomatically in the human body. Methicillin resistant S. aureus (MRSA) strains have a gene that makes them resistant to almost all betalactam drugs. Resistance to other antibiotics is also common, especially in hospital-associated MRSA. These organisms are dangerous nosocomial pathogens, and finding an effective treatment can be challenging. In some regions, community-associated MRSA strains, which originated outside the hospitals, are also common. While these organisms have generally been easier to treat, some have moved into hospitals and have become increasingly resistant to drugs other than beta-lactams.¹

Methicillin resistant S. aureus was reported soon after its introduction in October 1960.² MRSA is now endemic in India. MRSA prevalence ranges from 25% in the western part of India³ to 50% in the southern part.⁴ India is reporting an increase in community-acquired MRSA (CA-MRSA).⁵

Prior to the discovery of penicillin, most of the of S. aureus strains were sensitive to this antibiotic but from 1945 onwards, penicillinase-producing (penicillinresistant) strains were encountered. Staphylococci quickly developed drug resistance after penicillin was introduced, and today less than 10% of the strains are sensitive to this antibiotic. Similarly, they have also developed resistance against sulfonamides and other antibiotics.⁶

MRSA can contaminate environmental surfaces that are frequently touched by the hands of carriers or patients with MRSA colonization/infection. There have been many studies in which the presence of MRSA contamination was determined,⁷ but no studies in which MRSA contamination on surface of NABL and nonNABL diagnostic centers and effectiveness of newer paradigms to reduce hospital infection in the COVID period was done.

MRSA can survive for hours, days, or even weeks on certain surfaces, like towels, razors, furniture, and athletic equipment. MRSA can infect anyone who come in contact with a contaminated surface.⁸

Coronavirus disease 2019 (COVID-19) has put a huge strain on health and social care systems and resources globally. The significance of infection prevention and control through measures such as hand hygiene, social distancing and self-isolation have now been emphasized at a societal level.⁹

Keeping your hands clean is one of the most important things you can do to avoid getting sick and spreading infections like MRSA. If soap and water are available, wash your hands with them. Scrub your hands at least for 20 seconds with soap. If soap and water are not available, clean your hands using an alcohol-based hand sanitizer containing at least 60% alcohol. Apply the sanitizer to one hand and rub it together to cover all the areas of your hands.⁸

Nosocomial infections are the fifth leading cause of death in critical-care hospitals. The prevalence of hospital acquired infections (HAI) in developing countries is neither recorded nor reported properly due to various reasons.¹⁰

Materials and Methods

This study was conducted for a period of one month from July 1 to 31, 2020, in Padmashree Diagnostic centre (NABL laboratory). We investigated MRSA contamination of highly touched surfaces in laboratories. Surface samples were taken from the locations such as waiting area, collection room, doorknob, reception desk, workbench, incubator knob, chair edges, faucet knob from different laboratories such as Padmashree, Trident, Suguna, Prakash, SRS and Kangaroo. The swabs were collected with sterile, cotton- tipped applicator (swab stick).

Method of inoculating of swabs

The plates of nutrient agar and mannitol salt agar were allowed to dry. The specimens were inoculated as soon as possible after the collection. The swab was rolled on the agar surface, streaked with a sterile loop to get isolated colonies and the plates were incubated at 37ºC for 24- 48 hours. The colony morphology was examined. With every batch, appropriate quality control Staphylococcus aureus ATCC® 6538 was used, and it produced golden yellow coloured colonies on media.

Expected growth on Mannitol Salt Agar

The colonies of gram positive Staphylococcus species which fermented mannitol turned yellow (S. aureus), while the gram positive Staphylococcus species not fermenting mannitol sugar did not change colour (e.g. S. epidermidis).

Subculture on Nutrient agar

Yellow colonies from Mannitol salt agar were subcultured on nutrient agar. After incubation at 37°C, they produced golden yellow colonies. Gram stain showed gram positive cocci arranged in clusters.

Catalase and tube coagulase tests were positive for golden yellow colonies from nutrient agar.

VITEK System (bioMe´rieux, France)

Golden yellow colonies which were positive for tube coagulase were further identified and antibiotic sensitivity test was done by VITEK 2 system. The VITEK 2 gram-positive (GP) identification card has been developed to improve the accuracy of grampositive cocci identification. The card contains 43 biochemical tests, including 17 enzymatic assays, which are interpreted in kinetic mode for up to 8 hours. The VITEK 2 Gram Positive Cefoxitin Screen use the antibiotics cefoxitin and oxacillin to screen for methicillin resistant Staphylococcus aureus (MRSA).¹¹

Results

This study included 84 swabs to determine the MRSA contamination of the environmental surfaces (waiting area, collection room, doorknob, reception desk, workbench incubator knob, chair edges, faucet knob) from six laboratories (NABL and Non-NABL). Two swabs were taken from each surface, one was inoculated into nutrient agar and other into mannitol salt agar.

The above table shows growth of organisms on nutrient agar and mannitol salt agar from different high contact surfaces of the NABL and Non NABL laboratories.

Table 2 shows that the growth of organisms was observed on nutrient agar plate from the swabs collected from all the three NABL and three Non NABL laboratories and on mannitol agar, only the swabs from Non NABL Laboratory 6 showed the growth of Staphylococcus aureus.

Discussion

In the present study, 50% growth was observed on nutrient agar with the swabs obtained from two of the NABL laboratories and 75% growth was observed from the other one. No growth was detected on mannitol salt agar from the swabs collected from any of the NABL laboratories. In case of non NABL laboratories, 50%, 75% and 87.5% growth on nutrient agar was observed respectively and 12.5% growth on mannitol salt agar was observed from the swabs of non NABL laboratory number 6.

In case of non NABL laboratory number 6, 87.5% growth on nutrient agar and 12.5% growth on mannitol salt agar was observed, mainly from reception desk surface area. In the COVID era, laboratories maintained proper hygiene; however in case of reception desk area, because of repeated movement and contact with patients and attenders, growth of Staphylococcus aureus could be detected. Surface sterilization is done with 1% sodium hypochlorite on non-metal surfaces and with alcohol for metal surfaces in both NABL and non NABL laboratories as per the protocol. In case of NABL laboratories, monitoring of check list regularly is maintained because of which the incidence of Methicillin resistant Staphylococcus aureus is characteristically less.

Before the COVID-19 outbreak era

Staphylococcus aureus continued to be a dangerous pathogen for both community-acquired as well as hospital-associated infections. Methicillin-resistant S. aureus (MRSA) is now endemic in India. MRSA prevalence ranges from 25% in the western part of India³ to 50% in the southern part of India.⁴ India is reporting an increase in community-acquired MRSA (CA-MRSA).⁵ MRSA may live in the environment for a long time.¹² MRSA contamination in the surrounding environment may play a major role in the transmission of MRSA infections.

In the COVID-19 outbreak era

The exceptional procedures that have been taken up in the face of Corona, including the obligatory hand disinfection of all those entering healthcare centers, the use of masks, the continuous disinfection of surfaces, the fumigation sterilization of healthcare centers twice a day, the continuous disinfection of surfaces and floors, helped prevent the infection. We found that the prevalence of bacteria on the surfaces was non-existent due to the above mentioned reasons, and this indicates the success of the measures taken to reduce MRSA infection and all multidrug resistant organism (MDR) by contact transmission.

A lot of research has been done that shows a correlation between increased hand cleanliness compliance, and a reduction in MRSA infection. It was also observed that these programmes are cost-effective. Despite extensive research, some questions remain unanswered- the link between hand hygiene and MRSA-related surgical site infections, and the role of contact precautions in the setting of low MRSA rates. In conclusion, improvement in hand hygiene compliance has been observed in recent years to reduce MRSA incidence. Nevertheless, there are still some unresolved questions that need to be investigated further.¹³

Conclusion

In conclusion, this study was conducted to assess the efficiency of the program of infection control in the period of peak COVID-19 outbreak in preventing the prevalence of methicillin resistant Staphylococcus aureus (MRSA).

The swabs were collected from high contact surfaces of six laboratories and based on the findings it was concluded that all the procedures followed were highly effective for the control of the prevalence of MRSA by contact contamination.

In this study, we only focused on the prevalence of MRSA on high contact surfaces in laboratories due to lockdown and restricted procedure during peak outbreak of COVID-19. Therefore we recommend further studies including all multidrug resistant microorganisms and pathogenic viruses and the effect of these infection control procedures on them.

Conflicts of Interest

None.