Streptococcus suis Isolates—Serotypes and Susceptibility to Antimicrobials in Terms of Their Use on Selected Repopulated Czech Pig Farms

Abstract

Streptococcus suis represents a primary health problem (such as meningitis, septicemia and arthritis in piglets and fatteners) in the swine industry worldwide and also an emerging zoonotic pathogen. In the Czech Republic, many pig farms repopulated their herds over the past decades to reduce morbidity and minimize treatment. The study analysed serotypes, sequence types and antimicrobial susceptibility in 39 S. suis isolates obtained from organs of diseased pigs from selected 16 repopulated farms with a history of S. suis-associated diseases and routine antimicrobial treatment with tulathromycin and/or amoxicillin. The analysis revealed diversity of collected isolates with regular occurrence of more than three serotypes per farm. The serotypes identified were 1/2 and 7, each in six isolates, followed by serotype 2 and 3 found in five isolates each, other serotypes were less frequent. Seven isolates were not typable by multiplex PCR and we also found sequence type of unknown type in thirteen isolates. The majority of S. suis isolates were resistant to clindamycin (n = 31), tetracycline (n = 29) and tilmicosin and tulathromycin (n = 28). On the other hand, with the exception of two isolates that were intermediately susceptible to penicillin and ampicillin, all isolates were susceptible to all three tested subgroups of beta-lactam antibiotics.

Comparative virulence and antimicrobial resistance distribution of Streptococcus suis isolates obtained from the United States

“…The most prevalent AMR element found among the isolates was tetO , followed by ermB, lsaE , lnuB , ant(9)-Ia , and ant(6)-Ia . While differences in MICs between countries have been described, high prevalence rates for macrolide and tetracycline resistance, along with low prevalence rates for β-lactam resistance have been previously reported ( Gurung et al, 2015 ; Aradanas et al, 2021 ; Dechene-Tempier et al, 2021 ; Hadjirin et al, 2021 ; Ma et al, 2021 ; Matiasovic et al, 2021 ; Cucco et al, 2022 ). This has been a global trend for several decades now, and the genetic basis for these resistances has been extensively studied ( Varela et al, 2013 ; Gurung et al, 2015 ; Seitz et al, 2016 ; Dechene-Tempier et al, 2021 ).…”

Characterisation of Streptococcus suis Isolates in the Czech Republic Collected from Diseased Pigs in the Years 2018–2022

“…Due to the similar pathogenicity of our S7ST29 and German S7ST29 isolates, we can speculate that the S7ST29 isolates present in the Czech Republic and Germany may represent the same strain. This possibility is supported, also, by extensive pig transfer between the Czech Republic and Germany [ 36 ].…”

How Streptococcus suis escapes antibiotic treatments

“…Because of the high resistance rates, the aforementioned antibiotics have been replaced by others, such as β-lactams of which the resistance rates have persisted low over time (Figure 1 A). For example, resistance rates of less than 10% to β-lactams were reported in Denmark (1995) [ 6 ], Spain (2000) [ 12 ], Poland (2004) [ 9 ], The Netherlands (2014) [ 13 ], and, more recently, in Czech Republic (2020) [ 14 ]. These data indicate that the development of β-lactam resistance is rather modest in S. suis .…”

“…For amphenicols, AMR rates remained very low in the last two decades, e.g . in Belgium (2013) [ 23 ], Denmark (2016) [ 21 ], and Czech Republic (2021) [ 14 ]. In contrast, AMR rates to pleuromutilins have been moderate, showing an increasing trend in recent years, with the highest reported rates in Denmark (24% in 2017) [ 24 ] and Czech Republic (31% in 2021) [ 14 ].…”

“…in Belgium (2013) [ 23 ], Denmark (2016) [ 21 ], and Czech Republic (2021) [ 14 ]. In contrast, AMR rates to pleuromutilins have been moderate, showing an increasing trend in recent years, with the highest reported rates in Denmark (24% in 2017) [ 24 ] and Czech Republic (31% in 2021) [ 14 ]. Overall, AMR rates to most antibiotics vary considerably between European countries.…”