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Virulence Volume 9, 2018 - Issue 1
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Research Paper

Impact of contusion injury on intramuscular emm1 group a streptococcus infection and lymphatic spread

L. E. Lamba Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London, UK;b Royal Centre for Defence Medicine, University of Birmingham, Birmingham, UKORCID Iconhttps://orcid.org/0000-0001-5779-7207View further author information
ORCID Icon,
M. K. Sigginsa Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London, UKView further author information
,
C. Scudamorec Harwell Science and Innovation Campus, MRC Harwell, Oxfordshire, UKView further author information
,
W. Macdonaldd Department of Bio-engineering, Royal School of Mines, Imperial College London, London, UKView further author information
,
C. E. Turnera Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London, UKView further author information
,
N. N. Lynskeya Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London, UKView further author information
,
L. K. K. Tana Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London, UKORCID Iconhttps://orcid.org/0000-0002-3822-497XView further author information
ORCID Icon &
S. Sriskandana Section of Infectious Diseases and Immunity, Department of Medicine, Imperial College London, London, UKCorrespondence[email protected]
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Pages 1074-1084 | Received 19 Feb 2018, Accepted 22 May 2018, Published online: 27 Jul 2018

Figures & data

Table 1. Exploratory study, lower respiratory tract GAS infection in presence or absence of trauma: muscle data.

Table 2. Exploratory study, lower respiratory tract GAS infection in presence or absence of trauma: systemic tissue data.

Figure 1. Diagram showing timing of contusion – infection model for exploratory studies.

Route of infection and duration of infection initiated at three time points following contusion (0, 24 and 48 hours).
Figure 1. Diagram showing timing of contusion – infection model for exploratory studies.

Table 3. Exploratory study, intravenous infection in presence and absence of trauma: muscle data.

Table 4. Exploratory study, intravenous infection in presence and absence of trauma: systemic tissue data.

Figure 2. Histological features in soft tissue with or without contusion.

Photomicrographs of H&E stained tissue sections 24 and 48 h following contusion. (representative of 12 per group). A. Control subcutaneous tissue at 24 h. B Focal inflammation in the subcutis of injured leg 24 hours after contusion. Arrow represents the area of injury with an inflammatory response. C. Control muscle tissue at 48 h D Injured muscle at 48 h after contusion with focal loss of myofibres and replacement by a mixed inflammatory response of neutrophils and macrophages.
Figure 2. Histological features in soft tissue with or without contusion.

Figure 3. Histological features in soft tissue are similar following infection without or with contusion.

H & E stained tissue sections following GAS thigh muscle infection. A Photomicrograph of GAS-infected thigh tissue 24 h after infection without contusion. B Photomicrograph of GAS-infected thigh tissue 24 h after contusion and GAS infection. Both sections show multifocal mixed inflammatory cell infiltrate with slight myodegeneration and cell lysis. Some haemorrhage is seen in A.
Figure 3. Histological features in soft tissue are similar following infection without or with contusion.

Figure 4. Quantification of GAS in different tissues following simultaneous contusion and local intramuscular GAS infection.

Mice were infected i.m. with emm1 GAS with or without simultaneous contusion to same limb under anaesthetic. GAS clearance was measured 24h following infection in (A) Thigh muscle; (B) Draining ipsilateral inguinal lymph node (black) and contralateral inguinal lymph node (grey); (C) Spleen (D) Blood. n = 18/group for substantive study (includes data from ) Horizontal bars represent the median. Significant difference was observed in bacterial load between contusion group and controls in ipsilateral lymph node in contrast to other tissues (muscle, contralateral lymph node, blood and spleen).NS, non significant difference; ***p < 0.005.
Figure 4. Quantification of GAS in different tissues following simultaneous contusion and local intramuscular GAS infection.

Figure 5. Emergence of hasABC promoter deletion variants during GAS infection in draining inguinal lymph node.

A Number of mucoid colonies and B. non-mucoid colonies in draining inguinal lymph nodes of contusion group compared to control mice (*p < 0.01). N = 18 per group (sub-analysis from ). C. Hyaluronan capsule production by mucoid and non-mucoid bacterial colonies isolated from the draining lymph node n = 10 per group (**p < 0.05). D. Deletion of 213bp (indicated by red dotted line box) in hasABC promoter region identified in all five hyper-encapsulated colony variants from lymph node. Deleted region includes P2 promoter, regulator sRNA hasS region, and CovR binding site for the P1 promoter [Citation25,Citation34]. Equivalent position of deletion in completed reference genome MGAS5005 (NC_007297.2) is indicated as 1,818,451-1818663bp. E. Colony morphology wild type emm1 parent strain and F. isogenic hasABC P2 deletion mutant strain
Figure 5. Emergence of hasABC promoter deletion variants during GAS infection in draining inguinal lymph node.

Figure 6. Impact of capsule promoter mutation on GASin ipsilateral lymph node.

A – D Intramuscular infection with GAS P2 promoter variant (P2) compared with parent emm1 GAS strain (WT) (n = 6 per group). GAS colonies were quantified after 3h infection in (A) Infected thigh muscle; (B) Draining inguinal lymph node or contralateral inguinal lymph node; (C) Spleen; (D) Blood. P2 mutant showed enhanced bacterial load in the draining lymph node compared to parent emm1 GAS strain and also in spleen at this time point despite similar load in thigh muscle (**p < 0.01). Horizontal lines represent the median.
Figure 6. Impact of capsule promoter mutation on GASin ipsilateral lymph node.
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Impact of contusion injury on intramuscular emm1 group a streptococcus infection and lymphatic spread
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