Ocorrência, resistência, virulência e diversidade genética de Staphylococcus pseudintermedius oriundos de processos infecciosos em animais de companhia

Abstract

In Brazil, the prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) as a cause of infectious diseases in companion animals remains unknown. The emergence of MRSP is a challenge in veterinary medicine as multidrug resistant strains may potentially result in treatment failures. This study provides an overview of the occurrence and characterization of multidrug- resistant MRSP strains from canine and feline clinical samples in Rio de Janeiro, Brazil. A total of 92 S. pseudintermedius isolates were investigated for biofilm formation, presence of virulence genes (sea, seb, sed, sec, seccanine, se-int, lukS-lukF, lukE-lukD, lukM, hla, hlb, hld, hlg, hglv, eta, etb, etd, siet and exi), methicillin susceptibility and presence of mec genes. Most of the isolates (92.0%, 81/88) were classified as biofilm producers. Among the virulence genes detected, 97.8% (90/92) of the isolates amplified the siet gene, which encode an exfoliated toxin of S. pseudintermedius, 87.0% (80/92) the se-int gene, a enterotoxin-gene related, and 12.0% (11/92) the gene encoding the LukE-LukD leukotoxin (lukE/D) bicomponent of S. aureus. No isolates amplified the remaining virulence genes. Regarding methicillin resistance, 22 (23.9%) were identified as MRSP by both methods tested (disk diffusion and broth dilution) and by the presence of the mecA gene. These strains were submitted to SCCmec typing which revealed that the dominant SCCmec were type II-III (81,8%; 18/22), followed by non-typeable SCCmec (13,6%; 3/22) and SCCmec IV (4,5%; 1/22). Furthermore, multidrug resistance (MDR) was found in all MRSP isolates. Four types of closely related spa were detected: t02 (72.2%, 13/18), t15 (16.6%, 3/18), t05 (5.6%, 1/18) and t06 (5.6%; 1/18). PFGE analysis allowed the identification of two clones and two related strains. MLST typing revealed three STs/CCs (ST/CC71, ST265/CC258, and ST282/CC45) never reported in Brazilian MRSP strains from clinical specimens. In addition, two new STs (NSTs) have been identified and will be submitted to the curator of the MLST database. The predominance of the ST/CC71-spat02-SCCmecII-III (54.5%, 12/22) worldwide strain among the strains evaluated was revealed. The comparative analysis of the typing methods used evidenced the importance of combined analysis for understanding the population structure of MRSP. The results confirm the importance of monitoring multidrug-resistant pathogens and the need of further studies in Brazil to determine the prevalence and the characteristics of MRSP in companion animals from this region, providing data that will support preventive and control measures.