Sterile Pyometra in Two Dogs

Antimicrobials administration, treatment outcome and bacterial susceptibility in canine pyometra cases subjected to ovariohysterectomy

Pyometra is a bacterial uterine infection that frequently affects intact older bitches. The treatment of choice is ovariohysterectomy, often associated with perioperative antimicrobial therapy. The aim of this retrospective investigation was to evaluate the antibiotic choice at different administration times (pre-surgery, at surgery/during hospitalization, and post-surgery) against complications and outcomes, considering the susceptibility profile of bacteria. The medical records of 51 bitches referred to the Veterinary Teaching Hospital of the University of Turin (January 2021-November 2023) and subjected to ovariohysterectomy and bacteriological examination (bacterial culture and susceptibility tests) of the uterine exudate, were analysed. All animals had a positive outcome without surgical site infections, with a longer hospitalization time in case of peritonitis or sepsis; antimicrobials were administered for an average of 7 days. Comparing the susceptibility of the isolated bacteria towards the antimicrobials administered before, during and after surgery, complete efficacy was observed in 42 %, 46 % and 50 % of cases, respectively. In addition, 5/16 peritonitis cases were treated with an in vitro ineffective antimicrobial, and 30 % of the bitches never received a fully effective antibiotic, according to susceptibility tests using the minimum inhibitory concentration method (MIC). Cephazolin resulted the best option for Escherichia coli, the most frequently isolated bacterium. Our study confirms that pyometra has a good prognosis following ovariohysterectomy and antibiotic administration. Monitoring the clinical evolution without changing the antibiotic according to bacterial susceptibility could represent the right choice in uncomplicated cases. Evaluation of outcomes without postoperative antibacterial treatment or with a shorter course would be another topic worth investigating, with the aim to judiciously reduce the use of antibiotics.

Canine Pyometra: A Short Review of Current Advances

Pyometra, characterized by the accumulation of purulent exudate in the uterus, is the most prevalent reproductive disease in canines. While the disease often begins with mild local symptoms, it can escalate into peritonitis, sepsis, and multi-organ dysfunction, thereby posing a significant threat to life. Despite the high incidence and recognized significance of canine pyometra, gaps persist in our understanding of its epidemiology, etiology, and pathogenesis. Recent studies have, however, broadened our comprehension of this disease, shedding light on potential new infection sources, etiologies, and the application of clinical predictive biomarkers and new therapeutic protocols. This study aimed to review the current understanding of canine pyometra, with particular emphasis on the latest research concerning its etiology and epidemiology. Furthermore, it addressed key research questions and proposed directions for future investigations into various facets of canine pyometra.

Antimicrobial resistance profile of extended-spectrum beta-lactamases, adenosine-monophosphate-cyclic, and carbapenemase-producing Gram-negative bacteria isolated from domestic animals

Background and Aim: The production of beta-lactamase enzymes, such as extended-spectrum beta-lactamase (ESBL), adenosine-monophosphate-cyclic (AmpC), and Klebsiella pneumoniae carbapenemase (KPC), is one of the most important mechanisms of bacterial resistance to antimicrobials. Gram-negative bacteria show significant resistance due to various intrinsic and acquired factors. These intrinsic factors include low permeability of the outer membrane, various efflux systems, and the production of beta-lactamases, while acquired factors include chromosomal mutation and acquisition of resistance genes by horizontal transfer. Mobile elements such as plasmids, integrative conjugative elements, mobilizable islands, or transposable elements are involved in horizontal transfer. At present, the Gram-negative pathogens of most concern are Acinetobacter baumannii, Pseudomonas aeruginosa, and those belonging to the Enterobacteriaceae family (e.g., Escherichia coli, K. pneumoniae, and Proteus mirabilis). This study aimed to evaluate the profile of antimicrobial resistance and the production of the enzymes ESBL, AmpC, and KPC, in 21 gram-negative bacteria isolated from domestic animals treated at the University Veterinary Hospital (HVU) of the Federal University of Western Bahia (UFOB). Materials and Methods: The biological samples (21) were inoculated to brain heart infusion broth, blood agar, and MacConkey agar and incubated for 24-72 h at 37°C. Gram staining and identification through biochemical tests and matrix-associated laser desorption/ionization time-of-flight mass spectrometry were conducted. To evaluate the antimicrobial resistance profile, the disk diffusion method was used, and 25 antibiotics were employed. For the detection of ESBL, the disk approximation method was applied using chromogenic agar. The presence of KPC was observed using chromogenic agar and the Hodge test. For AmpC evaluation, the disk approximation method was used. Results: The most isolated agent was E. coli (66.66%, 14/21), followed by K. pneumoniae and P. mirabilis (both 14.29%, 3/21), and then Pasteurella spp. (4.76%, 1/21). The bacterial isolates showed high levels of resistance against clindamycin, penicillin, imipenem, polymyxin, cefoxitin, gentamycin, cefotaxime, ceftazidime, cephalothin, ceftriaxone, ciprofloxacin, trimethoprim/sulfamethoxazole, chloramphenicol, and tetracycline. The best effectiveness rates were observed for cefepime, streptomycin, amoxicillin-clavulanate, aztreonam, nalidixic acid, tobramycin, levofloxacin, amikacin, and meropenem. All biological isolates showed multiple resistance to at least three of the antibiotics tested (3/25), and some showed resistance to 24 of the antibiotics tested (24/25). Among the 21 pathogens analyzed, 8 were ESBL producers (38.09%); of these, 6 were identified as E. coli (28.57%), and 2 were identified as K. pneumoniae (9.52%). Two strains of K. pneumoniae produced both ESBL and KPC. None of the isolates were producers of AmpC. Conclusion: The results found in the present work raise concern about the level of antimicrobial resistance among pathogens isolated from domestic animals in Brazil. The results highlight the need for the development and implementation of anti-resistance strategies to avoid the dissemination of multiresistant pathogens, including the prudent use of antimicrobials and the implementation of bacterial culture, antimicrobial sensitivity, and phenotypic tests for the detection of beta-lactamase enzymes in bacteria isolated from animals.