A study of the transmission pathways of organisms associated with nosocomial infections at a veterinary academic hospital

Abstract

Background: Hospital-acquired infections (HAIs) are a major concern in human and veterinary medicine. They are caused by bacterial organisms mainly from the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). Within the veterinary settings, this group of organisms is often zoonotic and tends to acquire resistance determinants. As a result, most of these bacteria are multidrug-resistant, which limits treatment options and patient prognosis. Organisms associated with HAIs are transmitted mainly through the hands of healthcare workers (HCWs), making hand hygiene the most effective measure to prevent and control infections in healthcare facilities. However, low compliance to hand hygiene has been reported in both human and veterinary hospitals, which increases the risk of transmission of HAIs and zoonotic organisms. To reduce the risk of transmission, a multimodal approach has been recommended. As such, this study aims to use a multimodal approach to assess the pre-intervention required to reduce the transmission of organisms associated with HAIs and zoonotic diseases at a veterinary academic hospital. Methods: In order to achieve the objectives of this study, a systematic literature review using the PRISMA method was undertaken to describe the organisms responsible for HAIs and zoonotic infections. In addition, antimicrobial resistance genes associated with these organisms were also described. Since the results of the systematic literature review showed there was limited information on the burden of ESKAPE pathogens in South Africa, data on dog clinical cases presented at the veterinary academic hospital between 2007 and 2013 were reviewed. Klebsiella pneumoniae and A. baumannii isolates were assessed in terms of their burden and antimicrobial resistance patterns. Hands of healthcare workers were also assessed for the presence of organisms associated with HAIs and zoonotic diseases using the polymerase chain reaction (PCR). In addition, each isolate was subjected to antimicrobial sensitivity testing following the Kirby-Bauer disk diffusion method. In order to assess the level of knowledge of veterinary students regarding the transmission of HAIs, a questionnaire survey was performed assessing the knowledge of students on infection prevention and control (IPC) and the transmission of organisms associated with HAIs. Results: Bacterial organisms associated with HAIs and zoonosis were reported from clinical cases, environmental surfaces, and items used during patient treatment and care. Staphylococcus species was the most reported organism, and some isolates seem to share similar clonal lineage to those reported in humans. In terms of resistant genes, the mecA gene was identified in both Methicillin- resistant Staphylococcus aureus (MRSA) and Methicillin- resistant Staphylococcus pseudintermedius (MRSP), the blaCMY-2 gene in E. coli and Salmonella spp., flo genes in E. coli, and the vanA gene in E. faecium isolates. Acinetobacter baumannii (n=20) and K. pneumoniae (n=56) isolates were isolated from bronchoalveolar lavage, foreign objects, bone, urine, skin, blood, ear, nasal, and oral cavity. Sixty percent (60%) of A. baumannii were multidrug-resistant (MDR) while 98% were MDR K. pneumoniae. Of the students tested (62), at least one of the ESKAPE pathogens were isolated from their hands. Escherichia coli was the most isolated (76%, 47/62), followed by E. faecium (52%, 22/62), P. aeruginosa (48%, 30/62). A. baumannii (47%, 29/62), K. pneumoniae (27%, 17/62), and S. aureus (24%, 15/62). Resistance to at least one antibiotic was high among E. coli isolates (100%, 9/9), followed by E. faecium (67%, 4/6), P. aeruginosa (100%, 13/13), A. baumannii (57%, 4/7), K. pneumoniae (100%, 7/7), and S. aureus (67%, 2/3). Only E. coli (42%, 5/12), E. faecium (40%, 2/5), P. aeruginosa (100%, 13/13), and S. aureus (33%, 1/3) were multidrug resistant. Of the 147 students interviewed most were female (69%, 102/147) followed by male (29%, 43/147). Two (1%, 2/147) students did not indicate their sex. Less than half (41%, 60/147) of the respondents indicated they heard about IPC practices. However, they were aware that jewellery, stethoscopes, ward telephones, and leashes are possible sources of pathogens associated with HAIs. Conclusion: Bacterial organisms associated with hospital-acquired and zoonotic diseases were reported from clinical cases, environmental surfaces, and items used in veterinary service. The hospital environment where there is human contact had the highest burden of organisms associated with HAIs. Moreover, the ESKAPE organisms were identified in the hands of the students working in the ICU. Organisms associated with HAIs in this study were often MDR which is likely to impact patient care and prognosis. In addition, if contaminated, students would likely pass on these pathogens to other persons and animals. The results of this study further support suggestions that human behaviour plays a crucial role in the transmission of HAIs in veterinary hospitals. The study also shows from the survey that students do not have a good understanding of IPC measures and their role in the prevention of HAIs and zoonotic diseases although taught during lectures.