Efficacy of an Enrichment Media for Increasing Threshold for Carbapenem-Resistant Enterobacteriaceae Screening

Use of a chromogenic medium with and without selective enrichment to screen for carbapenemase-producing Enterobacterales (CPE) from canine and feline fecal specimens during an outbreak of NDM-5-producing Escherichia coli

Carbapenemase-producing Enterobacterales (CPE) are one of the most urgent threats to human healthcare globally. Descriptions of CPE outbreaks in veterinary hospitals suggest the need for screening strategies for CPE from companion animals. Our aim was to optimize a chromogenic agar method with and without selective enrichment to isolate CPE from companion animal feces in an ongoing outbreak of New Delhi metallo-β-lactamse-5 Escherichia coli. A limit of detection (LOD) assay for spiked canine and feline feces was performed for both methods using a carbapenamase-producing E. coli (24213-18); the LOD (1.5 × 103 cfu/g of feces) was equivalent to that reported for human fecal specimens. We screened 1,247 companion animal fecal specimens for carriage of CPE by 1) direct plating to chromogenic agar and 2) plating to chromogenic agar following selective enrichment. Twenty-one specimens were positive for CPE by both direct culture and enrichment culture. No specimens were positive with selective enrichment and negative by direct culture. A selective enrichment step did not result in any increased recovery of CPE from companion animals, which suggests that enrichment broth may not be necessary for outbreak surveillance testing. It is important to continue to validate methods for the detection of CPE in companion animals as outbreaks become more common in veterinary facilities.

A review of horses as a source of spreading livestock-associated methicillin-resistant Staphylococcus aureus to human health

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was first discovered in horses in 1989. Since then, LA-MRSA has begun to be considered an important strain of pathogenic bacteria in horses, which can cause LA-MRSA infection and colonization in humans with public health impacts. The anterior nares are the primary site of LA-MRSA colonization in horses, although LA-MRSA colonization may also occur in the gastrointestinal tract in horses. LA-MRSA-infected horses typically exhibit clinical infection or may not exhibit clinical infection. There are two potential risks associated with LA-MRSA colonization in horses: The possibility of disease development in horses infected with LA-MRSA and the possibility of LA-MRSA transfer to humans and other horses. The diagnosis of LA-MRSA in horses can be made by conducting in vitro sensitivity testing for oxacillin and cefoxitin, and then followed by a molecular test using polymerase chain reaction. LA-MRSA transmission in animal hospitals and on farms is most likely due to contact with horses infected or colonized by LA-MRSA. The history of prior antibiotic administration, history of prior LA-MRSA colonization, and length of equine hospitalization were described as risk factors in cases of infection and colonization of LA-MRSA in horses. Nebulized antibiotics may be a viable alternative to use in horses, but nebulized antibiotics are only used in horses that are persistently colonized with LA-MRSA. Controlling the spread of LA-MRSA in horses can be done by regularly washing horses, eradicating vectors in horse stalls such as rats, and maintaining the cleanliness of the stable and animal hospital environment. Meanwhile, cleaning hands, using gloves, and donning protective clothes are ways that humans can prevent the transmission of LA-MRSA when handling horses. This review will explain the definition of LA-MRSA in general, LA-MRSA in horses, the epi­demiology of LA-MRSA in horses, the diagnosis of LA-MRSA in horses, the transmission of LA-MRSA in horses, risk factors for spreading LA-MRSA in horses, public health impact, treatment of LA-MRSA infection in horses, and control of the spread of LA-MRSA in horses.

[Brain-heart media for blood cultures.]

When diagnosing bloodstream infection (BI) the culture medium is the basis for growth of microorganisms and obtaining the blood culture. Pancreatic digest from fish meal is the basis of all culture media in Russia. In European countries brain-heart media (BHM) are used for detecting microorganisms in blood. In Russia BHM is not produced. The aim is to work out the formulation and the way of the BHM (broth and agar) preparation in order to improve the efficiency of obtaining blood culture. There were defined the physical and chemical indices and biological parameters of the BHM. The microbiological control of the BHM was carried out by diagnostic study of cardiological patients' blood. On the basis of the developed technique of the brain-heart extraction (BHE) preparation there was created the liquid and agar BHM (LBHM, BHA). The LBHM was poured into bottles which then were filled with the inert gas. The bottles were closed with rubber stoppers and rolled in metal caps became a closed system. Microbiological qualities of LBHM were tested on 260 blood samples and thioglycollate medium (TGM) and LBHM. Aerobic microorganisms grew in LBHM 2,4 times more often than in TGM. The microaerophilic microbes grew in LBHM 3,2 times more often than in TGM. Anaerobic microbes did not show any growth in TGM, (p<0,001). Monomicrobes hemocultures were obtained in LBHM 13,4 times more often than in glucose broth and 2,3 times more often than in TGM, (p<0,001). Polymicrobes hemocultures were obtained in LBHM more often than in TGM (7,3% and 1,7%, respectively). The quality of brain-heart agar (BHA) was tested on 300 blood samples in 5% blood meat-pepton agar (MPA) and BHA in aerobic and anaerobic conditions for both the media. Aerobic microorganisms grew in BHA 2 times more often than in MPA. The microaerophilic microbes grew in BHA 3,6 times more often than in MPA. In anaerobic condition in BHA aerobic microorganisms grew 2 times more often than in MPA and the microaerophilic microbes grew 2,5 times more often than in MPA, (p<0,001). Anaerobic microbes did not grow in MPA. When diagnosing bloodstream infection the BHM (liquid and agar) are able to create the optimal conditions for the increase of the wide range pathogen growth.

Carbapenemase-producing Enterobacteriaceae in animals and methodologies for their detection

Carbapenemase-producing bacteria are difficult to treat and pose an important threat for public health. Detecting and identifying them can be a challenging and time-consuming task. Due to the recent rise in prevalence of infections with these organisms, there is an increased demand for rapid and accurate detection methods. This review describes and contrasts current methods used for the identification and detection of carbapenemase-producing bacteria to help control their spread in animal populations and along the food chain. The methods discussed include cultures used for screening clinical samples and primary isolation, susceptibility testing, culture-based and molecular confirmation tests. Advantages and disadvantages as well as limitations of the methods are discussed.