Bacterial Cross-Contamination in a Veterinary Ophthalmology Setting

Abstract

The present study describes the prevalence of bacterial cross-contamination in a veterinary ophthalmology setting, a serious issue that can result in healthcare-associated (or nosocomial) infections among patients and staff. Retrospective (n = 5 patients) and prospective (n = 23 patients) studies evaluated bacterial isolates in companion animals presenting with ulcerative keratitis, sampling the patients' cornea and surrounding examination room, including the environment (exam table, countertop, floor) and ophthalmic equipment (slit lamp, transilluminator, direct ophthalmoscope, indirect headset, tonometer). Results of bacterial culture and antibiotic susceptibility testing were recorded, and degree of genetic relatedness was evaluated in six pairs of isolates (cornea + environment or equipment) using pulse-field gel electrophoresis (PFGE). Overall contamination rate of ophthalmic equipment, environment, and examination rooms (equipment + environment) was 42.9% (15/35 samples), 23.7% (9/38 samples) and 32.9% (24/73 samples), respectively. Methicillin-resistant Staphylococcus pseudintermedius (MRSP), a multi-drug resistant (MDR) pathogen with zoonotic potential, was isolated in 8.2% (6/73) of samples. The patient's cornea was likely the source of cross-contamination in 50% (3/6) of MRSP pairs as evaluated by PFGE; notably, two of the three similar bacterial strains did not have an exact match of their antibiotic susceptibility profiles, highlighting the importance of advanced diagnostics such as PFGE to assess cross-contamination in healthcare facilities. Future work could examine the contamination prevalence of specific equipment or the efficacy of cleaning protocols to mitigate cross-contamination in veterinary practice.

Impact of multi-drug resistance on clinical outcomes of dogs with corneal ulcers infected with Staphylococcus pseudintermedius

“…Clinicians could also increase their level of suspicion for MDR strains by identifying risk factors in their canine patients. Here, a major risk factor for MDR infections was recent anesthesia prior to developing corneal ulceration, possibly related to anesthesia-associated reductions in lacrimation ( 37 )—lowering corneal protection and levels of natural defenses in the tear film (e.g., antimicrobial peptides)—as well as the presence of environmental contaminants in the vicinity of the anesthetized dog that could result in nosocomial infection ( 15 ). Another risk factor for MDR infections is a higher number of daily ophthalmic medications/eyedrops prior to referral, likely owing to natural selection of resistant bacteria from repeated antibiotic use ( 38 ) and the influence of corticosteroid use on bacterial keratitis ( 39 , 40 ).…”

“…First, corneal cultures help identify the causative pathogen and therefore provide clinicians with valuable insight on drug(s) of choice and clinical prognosis. Second, MDR identification provides critical data for healthcare professionals to reduce the risk of nosocomial infections (e.g., disinfection and sterilization of contact areas) ( 15 ) and to ensure surveillance of any emergent antibacterial resistance. Last, owners of canine patients with MDR strains should ideally be kept informed given the zoonotic potential of Staphylococcus pseudintermedius ( 13 , 14 ).…”

“…A component of normal flora in canines, Staphylococcus pseudintermedius is increasingly recognized as a major pathogen in various body systems of dogs including eyes, skin, ears, respiratory tract, reproductive tract, and urinary tract ( 11 , 12 ). Staphylococcus pseudintermedius is also an emerging pathogen in humans ( 13 ) with reported transmission from infected dogs to the home environment and owners ( 14 ), as well as cross-contaminations to other veterinary patients in clinical settings ( 15 ).…”

Zoonotic Staphylococcus spp. among domestic animals in Ukraine: antibiotic resistance and diagnostic approaches

“…In Thailand, S. pseudintermedius was detected in a newly constructed hospital, with strains showing resistance to disinfectants (Fungwithaya et al, 2022). Contamination of the environment and equipment of the ophthalmology office can occur with strains that cause infection or colonize other areas of the body of sick dogs (Gentile et al, 2020). Protocols for disinfecting equipment and the environment in hospitals need to be improved to effectively combat staphylococci that have the potential to become nosocomial agents.…”

Longitudinal environmental Staphylococcus contamination in a new small animal veterinary hospital and utility of cleaning checklists

“…While most SA and SP infections are often easily treatable, the methicillinresistant counterparts of these pathogens (MRSA and MRSP) are causes of human and veterinary healthcare-associated infections (HAI) (Johnson, 2002;Prevention, 2016). The hospital environment is speculated to play an important role in the overall transmission of staphylococci, with environmental contamination frequently identified in human and veterinary facilities and evidence of transmission between veterinary patients and clinic staff (Faires et al, 2013;Fernando et al, 2017;Febler, 2018;Gentile, 2020;van Balen et al, 2013;Murphy et al, 2010). Patients, owners and staff are potentially at risk due to their exposure to contaminated hospital surfaces.…”