Your role in curbing the rising threat of ophthalmic MRSA

Incidence rose more that 50%, a recent study reports. How you can stem the rise.

By Jerry Helzner, Senior Editor

The problem of antibiotic-resistant infections is widespread and encompasses many medical specialties and diseases. But specific to the ophthalmic setting, a landmark study of methicillin-resistant Staphylococcus aureus (MRSA) infections of the eye and the orbit at a major Northern California health-care system point to an increasing incidence of MRSA and often-inappropriate treatment.¹

MRSA was found to be more common in the eyelid/orbit (53%) followed by ophthalmic involvement such as conjunctivitis and corneal ulcer (35%).

SOURCE: KAISER PERMANENTE

This article will primarily deal with findings from a large, retrospective, eight-year study that analyzed 399 ophthalmic MRSA cases in the Kaiser Permanente Northern California health-care system. Malena Amato, MD, a Kaiser Permanente ophthalmologist and lead study author, worked with researchers from Stanford University and the University of California San Francisco to arrive at these findings, which highlight a widespread lack of knowledge in the proper treatment of these infections.

ALARMING FINDINGS

Rising resistance, inappropriate treatments

Although the Kaiser Permanente study delved into numerous aspects of these ocular and orbital MRSA cases, including demographics, risk factors, ophthalmic manifestations and treatment modalities, two of the findings were particularly alarming.

First, the incidence of antibiotic resistance increased from 31% in the first four years of the study (2002–2005) to 48% in the second four years (2006–2009) — a 55% increase — an indication that fewer antibiotics are capable of being efficacious against ocular MRSA.

Second, the researchers found 44% of the 399 cases studied were initially treated inappropriately. The inappropriate or ineffective treatments involved erythromycin, cephazolin, bacitracin, neomycin, polymixin and flouroquinolones. Only vancomycin, oral trimethoprim-sulfamethoxazole and rifampin were effective against all isolates, with topical gentamicin and chloramphenicol also effective in many of the cases studied.

“It is critical to recognize the emergence of resistant organisms, especially to topical bacitracin and flouro-quinolones, which have been mainstays of therapy for ocular infections,” the Kaiser Permanente report cautioned. “Many physicians use erythromycin or bacitracin to treat common ocular infections, particularly in newborns, however MRSA was frequently found to be resistant to these agents in our study.”

CDC: MRSA a ‘serious’ threat

The Kaiser Permanente study, which specifically focused on ophthalmic MRSA, is just one battle in a much wider war against antibiotic-resistant infections.

CDC focuses on MRSA prevention

The CDC has issued guidelines to prevent the spread of MRSA in clinical settings. The list of precautions here are general standards for all medical practices. Additional MRSA control measures in serious outbreaks may include identification and decontamination of individuals — particularly health-care workers — who are MRSA transmitters. These transmitters, estimated by the CDC at approximately two out of every 100 people, carry the MRSA bacteria in their nasal passages, but do not become ill from it. It is worth noting that some ophthalmologists performing intravitreal injections attempt to reduce the (very small) possibility of infection by wearing gloves, masks and not speaking with the patient during the injection procedure. Hand hygiene. Perform hand hygiene (CDC recommends hand washing or alcohol-based hand rubs) after touching blood, bodily fluids, secretions and contaminated items, whether or not gloves are worn. Perform hand hygiene immediately after removing gloves, between patient contacts and when otherwise indicated to avoid transfer of microrganisms to other patients or environments. When hands are visibly soiled with blood or other bodily fluids, wash hands thoroughly with soap and water. It may be necessary to perform hand hygiene between tasks and procedures on the same patient to prevent cross-contamination of different body sites. Gloving. Wear gloves when you can reasonably anticipate coming into contact with blood or other potentially infectious materials, mucous membranes, non-intact skin or potentially contaminated intact skin. Remove gloves after contact with a patient or the surrounding environment (including medical equipment), using proper technique to prevent hand contamination. Do not wash gloves for reuse or wear the same pair of gloves for more than one patient. Mouth, nose, eye protection. Protect the mucous membranes of the eyes, nose and mouth during procedures and patient-care activities that are likely to generate splashes or sprays of blood, body fluids or secretions. Select masks, goggles, face shields and combinations of each according to the need anticipated by the task performed. Gowning. Wear a gown appropriate for the task, to protect skin and prevent soiling or contamination of clothing during procedures and patient-care activities when you anticipate contact with blood, body fluids or secretions. Appropriate handling of equipment, instruments and devices. Handle used patient-care equipment soiled with blood, body fluids and secretions in a manner that prevents skin and mucous membrane exposures, contamination of clothing, and transfer of microorganisms to other patients and environments. Ensure that reusable equipment is not used for the care of another patient until it has been appropriately cleaned and reprocessed and that single-use items are properly discarded. Clean and disinfect surfaces likely to be contaminated with pathogens, including those in close proximity to the patient and frequently touched surfaces in the patient care environment, such as door handles and surfaces in and surrounding toilets. Appropriate handling of laundry. Handle, transport, and process used linens to avoid contamination of air, surfaces and persons.

Methicillin-resistant Staphylococcus aureus (MRSA) is the bacterium responsible for several difficult-to-treat infections.

Just two months ago, the Centers for Disease Control and Prevention (CDC) issued a major report on the growing threat of antibiotic-resistant infections, estimating more than 2 million Americans are contracting these infections each year.²

The CDC report noted that the problem largely stems from overuse or unnecessary use of antibiotics that has allowed rapidly evolving bacteria to develop resistance to anti-microbial drugs. The CDC cited the haphazard prescribing of antibiotics for common colds, flu, ear infections and non-strep sore throats, which are caused by viruses and are not helped by antibiotics, as a key contributor to growing antibiotic resistance.

In the report, which was directed to the general public as well as health-care workers, the CDC categorized these types of infections as “urgent threats,” “serious threats” or “concerning threats.” MRSA is in the “serious” category, along with two types of drug-resistant salmonella, drug-resistant tuberculosis and drug-resistant Candida fungus.

In releasing the report Thomas Frieden, MD, MPH, sounded this alarm: “We talk about a pre-antibiotic era and an antibiotic era. If we're not careful, we'll be in a post-antibiotic era. For some patients and some microbes, we're already there.”

Surgical treatment of ophthalmic MRSA

Despite the 44% incidence of ineffective initial treatment in the Kaiser Permanente study, MRSA patients whose cases were resolved medically either received first-line treatment with effective antibiotics, or were eventually transitioned from an inappropriate treatment regimen to an effective regimen.

A limited number of patients eventually underwent surgery. Twenty-six percent underwent incision and drainage, while 19% underwent other surgeries, including dacryocystorhinostomy, removal of scleral buckle and foreign-body removal. None of the patients in the Kaiser Permanente study sustained permanent visual loss.

PROVOCATEURS OF OCULAR MRSA

Risk factors

The researchers identified the two leading risk factors for ophthalmic MRSA infection: multiple sites of infection on the body and an immune compromise status, possibly caused by an underlying condition such as cancer, heart disease, HIV, hepatitis, asthma or other conditions that affect the immune system. However, diabetes did not rank as a significant risk factor for ophthalmic MRSA.

Additional potential risk factors the investigators found not statistically significant were other household or family members with MRSA, previous trauma or recent surgery.

Ophthalmic manifestations

The Kaiser Permanente study found the most common ophthalmic manifestations of MRSA were conjunctivitis, eyelid abscess, cellulitis and dacryocystitis (chart). Approximately 13% of the MRSA cases were in infants, with 77.5% of the infants studied presenting with conjunctivitis.

Causes of neonate MRSA ranged from exposure to the hospital environment, maternal transmission or frequent exposure to antibiotics. The researchers cautioned that MRSA-related orbital or ophthalmic infections “can have an aggressive disease course, raising concern for early recognition and treatment.”

Means of MRSA transmission

MRSA infections can be acquired in two different ways: health-care-associated MRSA or community-acquired MRSA. Most cases of the former are transmitted in the hospital setting, whereas community-acquired MRSA often comes from close proximity, such as active team sports where towels are shared and open cuts from body-to-body contact form an easy basis for transmission.

The Kaiser Permanente investigators found 302 of the cases to be community-acquired and 97 health-care-associated. Community-acquired cases had a higher incidence in younger adults and infants, but health-care-acquired cases showed no specific demographic trend.

Women comprised 52% of all the cases reviewed and males accounted for 48%. Of those cases for which ethnicity was recorded, Caucasians represented 47% of the patients, Hispanics 18%, African-Americans 12% and Asians 10%.

Conclusions

In the Kaiser Permanente study, the researchers concluded “MRSA of the eye and orbit can range from mild to severe sight-threatening disease, in which case early recognition, proper antibiotic selection and surgical intervention when it is indicated is critical” OM

REFERENCES

1. Amato, M, Pershing, S, Walvick, M, Tanaka, S. Trends in methicillin-resistant staph aureus infections of the eye and orbit. Presented at: Annual Meeting of American Academy of Ophthalmology; October 2011; Orlando, FL.

2. US Centers for Disease Control and Prevention. Antibiotic/ antimicrobial resistance Threat Report 2013. Available at: www.cdc.gov/drugresistance/threat-report-2013/index.html. Accessed November 2, 2013.