Practical relevance: Cat breeders aim to suppress the sexual cycle for a defined period. This is a challenge as most preparations available for this intention are orally administered progestins; however, these drugs may have side effects, especially when used over a long period of time. Long-acting gonadotropin-releasing hormone agonist implants have been used successfully to suppress the oestrous cycle in cats for a longer period. After removal of the implant, the duration of action was shortened; however, the re-occurrence of normal cyclicity cannot be foreseen. The search for alternatives is therefore ongoing. Clinical challenges: Another possibility for oestrus control is orally administered melatonin preparations; however, previous studies have shown that the effect was not satisfactory. After subcutaneous application of a melatonin implant developed for induction of oestrus in sheep (Melovine; Ceva Santé Animale), duration of oestrus suppression was shown to differ highly in individuals and in some cases no effect was observed. Nevertheless, it is used for short-term oestrus suppression in female cats. Aims: This article provides an overview of recent studies and clinical experiences of the use of melatonin as a contraceptive in cats. It explains the function of melatonin in cats, discusses previous studies, provides clinical experience with Melovine (27 cases) and elucidates advantages and disadvantages. Evidence base: Information provided in this article is drawn from the published literature and the author’s own clinical experience.

The aim of the present study was to characterize Enterobacterales resistant to 3rd and 4th generation cephalosporins, carbapenems and/or fluoroquinolones, isolated from dogs and cats with urogenital infections. In total, 36 strains (Escherichia coli (n = 28), Klebsiella pneumoniae (n = 3), Serratia marcescens, Raoultella ornithinolytica, Proteus mirabilis, Citrobacter portucalensis and Enterobacter cloacae (each n = 1)) were included in the present study, 28 from Austria and 8 from Serbia. Isolates were characterized by a polyphasic approach including susceptibility pheno- and genotyping and microarray-based assays. Escherichia (E.) coli isolates were additionally characterized by two-locus (fumC and fimH) sequence phylotyping and multi-locus sequence typing (MLST) of selected isolates. MLST of carbapenem-resistant Enterobacter cloacae isolates was also performed. Among E. coli, the most dominant phylogenetic group was B1 (27.8%), followed by C, (16.6%), A and Clade II (5.5% each), B2 and F (2.77% each). The most predominant β-lactam resistance genes were bla_TEM (70%) and bla_CTX-M (38.8%), bla_CMY (25%). bla_NDM was detected in one carbapenem-resistant Enterobacter cloacae ST114. The most common ST among selected E. coli was 744 (10.7% isolates). The pandemic clones ST131 and ST648 carrying CTX-M-15 were also detected. Remaining STs belonged to 469, 1287, 1463 and 1642. E. coli clonotyping revealed 20 CH types. Based on the presence of certain virulence genes, three isolates were categorized as ExPEC/UPEC. The most prevalent virulence factors were fimH detected in 61%, iucD and iss both in 55%, iroN in 27.8%, papC in 13.8% and sat in 8.3% isolates.