Neutrophils in Streptococcus suis Infection: From Host Defense to Pathology

Bleuzé, Marêva; Gottschalk, Marcelo; Segura, Mariela

doi:10.3390/microorganisms9112392

Cited by 11 publications

(17 citation statements)

References 148 publications

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“…This is expected, as neutrophils are the main immune cell present in bacterial meningitis [ 11 ]. In particular, S. suis infection is characterised by neutrophilic leukocytosis, and lesions of infected subjects contain a large number of neutrophils, as recently extensively reviewed [ 12 ]. Demonstrating the presence of neutrophils may, therefore, assist swine practitioners in the early stages to predict bacterium-induced meningitis and initiate antimicrobial treatment early [ 13 , 14 ].…”

Section: Discussionmentioning

confidence: 99%

“…There were many smears, especially in the group with a moderate or low number of neutrophils, that contained other more heterogeneous cell clusters. It is known that, especially during an ongoing period of the disease, bacterial infections will lead to infiltration of neutrophils, as well as mononuclear inflammatory cells, e.g., macrophages, lymphocytes, and plasma cells [ 5 , 12 ]. In addition, different Streptococcus spp.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, different Streptococcus spp. may induce disease via different pathogeneses and, therefore, a morphologically variable inflammatory response in the animal, which could result in presence of more heterogeneous inflammatory cell populations in the meninges [ 12 , 16 ]. This may also explain the lower predictive values (74%) of smears with a low number of neutrophils for the negative result of bacterial culture, i.e., smears with no or a low number of neutrophils, but where the bacterial culture was positive.…”

Section: Discussionmentioning

confidence: 99%

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Microscopical Evaluation of Smears of the Leptomeninges to Predict Meningitis in Piglets

Schyns¹,

Maes

Kuller³

et al. 2022

Veterinary Sciences

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Meningitis, caused by bacterial infections such as Streptococcus spp., is a frequently observed cause of death in pigs. In order to implement effective treatment and avoid further losses, it is important to establish this diagnosis quickly. However, this is often difficult because macroscopic lesions may not be visible, and additional laboratory testing may take several days. The present study investigated whether microscopical examination of impression smears of the leptomeninges taken during necropsy can help in establishing a presumptive diagnosis of meningitis in pigs more quickly. In total, 54 pigs suffering from neurological signs and/or (acute) mortality were examined. They were 3 to 10 weeks old and originated from 16 farms. From each pig, bacterial culture was performed on one half of the brain using a swab from the leptomeninges. From the other half, paired cytological impression smears of the leptomeninges were stained with a commercial quick stain dye (Hemacolor®) and Gram stain and microscopically evaluated for the abundance of neutrophils and the presence of short-chain coccoid bacteria. Bacterial culture of the leptomeninges was positive in 36/54 cases, in 28 of which Streptococcus spp. were found. The numbers of smears with low, moderate, or high abundance of neutrophils were 19, 17, and 18, respectively. Short-chain coccoid bacteria were detected successfully in 12 pigs in the Gram-stained smear. The positive predictive value of smears with moderate or high abundance of neutrophils for bacterial presence and, therefore, likely meningitis was 89%, whereas the negative predictive value of smears with low abundance of neutrophils was 74%. The positive predictive value of smears with short chains of coccoid bacteria for diagnosis of Streptococcus spp. was 100%, whereas the negative predictive value was 62%. In conclusion, microscopical examination of impression smears of the leptomeninges of piglets with neurological signs and/or (acute) mortality is a feasible procedure that can help swine practitioners in establishing a tentative diagnosis of meningitis more quickly, especially if neutrophils are abundant, and short chains of coccoid bacteria are present.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Microscopical Evaluation of Smears of the Leptomeninges to Predict Meningitis in Piglets

Schyns¹,

Maes

Kuller³

et al. 2022

Veterinary Sciences

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“…S. suis produces a pore-forming cholesterol-dependent cytolysin (Suilysin) [ 41 , 42 , 43 ]. The different effects of this toxin on neutrophils are discussed [ 44 , 45 ].…”

Section: Introductionmentioning

confidence: 99%

New Insights into Neutrophil Extracellular Trap (NETs) Formation from Porcine Neutrophils in Response to Bacterial Infections

Bonilla

Quiros

Wendt

et al. 2022

IJMS

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Actinobacillus pleuropneumoniae (A.pp, Gram negative) and Streptococcus (S.) suis (Gram positive) can cause severe diseases in pigs. During infection, neutrophils infiltrate to counteract these pathogens with phagocytosis and/or neutrophil extracellular traps (NETs). NETs consist of a DNA-backbone spiked with antimicrobial components. The NET formation mechanisms in porcine neutrophils as a response to both of the pathogens are not entirely clear. The aim of this study was to investigate whether A.pp (serotype 2, C3656/0271/11) and S. suis (serotype 2, strain 10) induce NETs by NADPH oxidase- or CD18-dependent mechanisms and to characterize phenotypes of NETs in porcine neutrophils. Therefore, we investigated NET induction in porcine neutrophils in the presence and absence of NET inhibitors and quantified NETs after 3 h. Furthermore, NETosis and phagocytosis were investigated by transmission electron microscopy after 30 min to characterize different phenotypes. A.pp and S. suis induce NETs that are mainly ROS-dependent. A.pp induces NETs that are partially CD18-dependent. Thirty minutes after infection, both of the pathogens induced a vesicular NET formation with only slight differences. Interestingly, some neutrophils showed only NET-marker positive phagolysosomes, but no NET-marker positive vesicles. Other neutrophils showed vesicular NETs and only NET-marker negative phagolysosomes. In conclusion, both of the pathogens induce ROS-dependent NETs. Vesicular NETosis and phagocytosis occur in parallel in porcine neutrophils in response to S. suis serotype 2 and A.pp serotype 2.

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“…Asymptomatic carriers (carrier animals) of S. suis are a source of infection for other pigs and are important in the transmission of this pathogen in herds. Streptococcus suis is resistant to various environmental conditions (Srinivasan et al, 2016;Bleuzé et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Detection of Streptococcus suis using the optimized real-time polymerase chain reaction protocol

Savcheniuk

Tarasov²,

Zakharova³

et al. 2022

Regul. Mech. Biosyst.

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The article presents the results of studies on the detection of Streptococcus suis by real-time polymerase chain reaction. Isolation and species identification of the studied isolates of streptococci was carried out according to morphological, cultural, biochemical and biological properties by conventional methods. The study of cultural characteristics of growth was carried out using conventional bacteriological methods on the brain heart infusion broth (BHI) and BHI agar with the addition of 5% sheep blood (blood BHI agar). To confirm biochemical properties as a confirmatory method, API 20 STREP test kit (bioMerieux, France) was used. In addition, to differentiate S. suis from the non-pathogenic species of streptococci, the hemolysis test was used. As a result of the studies, it was found that the use of the real-time PCR (polymerase chain reaction) method makes it possible to detect S. suis in an amount of 1 x 104 genome copies in the sample. All described validation parameters for the qualitative detection of S. suis DNA by real-time PCR meet international requirements, which guarantees accurate and reliable results. In Ukraine only a diagnostic test kit for convential PCR has been developed for the detection of swine streptococcosis. This approach is more time consuming and complex in comparison with the real-time PCR approach. We recommend that diagnostic laboratories implement this method in their practice. This will increase the number of effective diagnostic tools available to veterinarians on pig farms when they order laboratory tests. The high analytical sensitivity limit of a test is an essential parameter when screening is the focus, and obtaining false negative results causes a risk of the development of infection process among pig populations within infected herds. Our study showed that microbiological diagnostic methods to determine morphological and cultural properties can identify S. suis at the genus level. Determination of biochemical properties using the API 20 STREP test kit can be used to identify S. suis 1 and 2 serotypes. The conventional method and real-time PCR have 100% specificity and can be used to identify S. suis of different serotypes. Real-time PCR is a 2 to 4 times more sensitive limit than conventional PCR depending on the serotype being studied, and can be used to more accurately identify streptococcal DNA. It was found that the use of the real-time PCR method makes it possible to detect S. suis in an amount of 1 x 104 copies of the genome in the sample. Additionally, it was found that all the studied validation parameters of the qualitative method for determining S. suis DNA by real-time PCR meet international requirements, which guarantees accurate and reliable results.

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Neutrophils in Streptococcus suis Infection: From Host Defense to Pathology

Cited by 11 publications

References 148 publications

Microscopical Evaluation of Smears of the Leptomeninges to Predict Meningitis in Piglets

Microscopical Evaluation of Smears of the Leptomeninges to Predict Meningitis in Piglets

New Insights into Neutrophil Extracellular Trap (NETs) Formation from Porcine Neutrophils in Response to Bacterial Infections

Detection of Streptococcus suis using the optimized real-time polymerase chain reaction protocol

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