Bilateral periprosthetic joint infection caused by Salmonella enterica serotype Enteritidis, and identification of Salmonella sp using molecular techniques

A case of a renal abscess caused by Salmonella bareilly in a previously healthy boy

Background

Renal abscesses are relatively uncommon in children, and usually due to Gram-negative rods or Staphylococcus aureus, whereas abscesses caused by Salmonella are very rare.

Case presentation

We present the case of a previously healthy 10-year-old boy who had a renal abscess due to Salmonella bareilly. He responded well to treatment with antibiotics, and computed tomography (CT)-guided drainage of the abscess. His blood, urine and abscess aspirate cultures were sterile, but a broad-range 16S rDNA polymerase chain reaction (PCR) assay of the aspirate followed by analysis of four Salmonella genes (fliC, fliD, sopE2, and spaO) identified S. bareilly as the causative agent.

Conclusion

To the best of our knowledge, this is the first report of renal abscess caused by S. bareilly.

The difference between native septic arthritis and prosthetic joint infections: A review of literature

Current literature occasionally considers septic arthritis in native joints and prosthetic joint infections as equal pathologies. However, significant differences can be identified. The aim of this review of literature is to describe these differences in definitions, pathology, diagnostic workups, treatment strategies, and prognosis.

Total hip arthroplasty infection caused by an unusual organism, Salmonella; its successful management and literature review

Prosthetic joint infection due to Salmonella spp is rare. Here we report an acute case of Salmonella enteritidis infection of a total hip arthroplasty in a man taking immunosuppressant medication. He was managed with antibiotics and two-stage revision surgery.

Unusual Salmonella typhi periprosthetic joint infection involving bilateral knees: management options and literature review

A 70-year-old Indian woman, who had undergone primary bilateral total knee arthroplasty (TKA) for rheumatoid arthritis 10 months prior, presented with 10 days history of pain, swelling and erythema over both knees with pus discharging from the right knee. She had type 2 diabetes mellitus and was on long-term steroid, leflunomide and antitumour necrosis factor therapy for rheumatoid arthritis. Her clinical and laboratory features were suggestive of a haematogenous periprosthetic joint infection (PJI). The final diagnosis of bilateral Salmonella typhi PJI was made based on culture reports. Considering her underlying immunosuppression, a bilateral two-stage revision TKA was done with complete remission of symptoms and good functional recovery at last follow-up after 18 months. S. typhi infection of prosthetic joint has not been reported in the literature. Patients presenting with gastrointestinal complaints and PJI should alert the clinician to the possibility of infection with such atypical organisms endemic to the region.

Immunogenicity and protective efficacy of a Salmonella Enteritidis sptP mutant as a live attenuated vaccine candidate

Background

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a highly adaptive pathogen in both humans and animals. As a Salmonella Type III secretion system (T3SS) effector, Salmonella protein tyrosine phosphatase (SptP) is critical for virulence in this genus. To investigate the feasibility of using C50336ΔsptP as a live attenuated oral vaccine in mice, we generated the sptP gene deletion mutant C50336ΔsptP in S. Enteritidis strain C50336 by λ-Red mediated recombination and evaluated the protective ability of the S. Enteritidis sptP mutant strain C50336ΔsptP against mice salmonellosis.

Results

We found that C50336ΔsptP was a highly immunogenic, effective, and safe vaccine in mice. Compared to wild-type C50336, C50336ΔsptP showed reduced virulence as confirmed by the 50% lethal dose (LD₅₀) in orally infected mice. C50336ΔsptP also showed decreased bacterial colonization both in vivo and in vitro. Immunization with C50336ΔsptP had no significant effect on body weight and did not result in obvious clinical symptoms relative to control animals treated with phosphate-buffered saline (PBS), but induced humoral and cellular immune responses at 12 and 26 days post inoculation. Immunization with 1 × 10⁸ colony-forming units (CFU) C50336ΔsptP per mouse provided 100% protection against subsequent challenge with the wild-type C50336 strain, and immunized mice showed mild and temporary clinical symptoms as compared to those of control group.

Conclusions

These results demonstrate that C50336ΔsptP can be a live attenuated oral vaccine for salmonellosis.

Periprostetic Joint Infection Caused by Salmonella: Case Reports of Two Azathioprine and Prednisolone Induced-immunocompromised Patients

Periprosthetic joint infection (PJI) due to Salmonella is rare. It frequently occurs patients receiving immunosuppressive medicine. We describe two periprosthetic Salmonella infection of two immunocompromised patients. Both of patients were receiving azathioprine and prednisolone therapy. First patient presented six years after total hip arthroplasty with a huge abscess on her right thigh that was reached to femoral component through the lytic area of lateral femur. Second patient presented with drainage from his hip and he had undergone two-step revision surgery for PJI 3 months ago. There is no consensus in the treatment of periprosthetic salmonella infections. We prefer two-step revision surgery for these infections as previously described in the literature.

Salmonella enteritidis Effector AvrA Stabilizes Intestinal Tight Junctions via the JNK Pathway

Salmonella pathogenesis studies to date have focused on Salmonella typhimurium, and the pathogenesis of a second major serotype, Salmonella enteritidis, is poorly understood. Salmonella spp. possess effector proteins that display biochemical activities and modulate host functions. Here, we generated a deletion mutant of the effector AvrA, S.E-AvrA^-, and a plasmid-mediated complementary strain, S.E-AvrA^-/pAvrA⁺ (S.E-AvrA⁺), in S. Enteritidis. Using in vitro and in vivo infection models, we showed that AvrA stabilizes epithelial tight junction (TJ) proteins, such as ZO-1, in human intestinal epithelial cells. Transepithelial electrical resistance was significantly higher in cells infected with S.E-AvrA⁺ than in cells infected with S.E-AvrA^- Inhibition of the JNK pathway suppresses the disassembly of TJ proteins; we found that enteritidis AvrA inhibited JNK activity in cells infected with wild type or S.E-AvrA⁺ strains. Therefore, Enteritidis AvrA-induced ZO-1 stability is achieved via suppression of the JNK pathway. Furthermore, the S.E-AvrA^- strain led to enhanced bacterial invasion, both in vitro and in vivo Taken together, our data reveal a novel role for AvrA in S. Enteritidis: Enteritidis AvrA stabilizes intestinal TJs and attenuates bacterial invasion. The manipulation of JNK activity and TJs in microbial-epithelial interactions may be a novel therapeutic approach for the treatment of infectious diseases.

Prosthetic joint infection due to Salmonella species: a case series

Background

Prosthetic joint infection (PJI) due to Salmonella is rare. Numerous outbreaks of Salmonella have been reported throughout the United States in the last decade. We reviewed and analyzed cases of Salmonella PJI seen at our institution.

Methods

The medical records of all patients diagnosed with a Salmonella PJI between 1969–2013 were reviewed. Patients were followed till death, treatment failure or loss to follow-up.

Results

Six patients of Salmonella PJI were identified during the 44 year study period. Five were male; median age was 63.5 years (range 52–76). Five patients were immunodeficient. Five had a total hip arthroplasty infection, while one had a total knee arthroplasty infection. Median prosthesis age at the time of diagnosis of first episode of Salmonella PJI was 5 years (range 4 months-9 years). Four presented with fever and constitutional signs within two weeks of symptom onset. Two patients each had gastrointestinal symptoms and Salmonella bacteremia. Salmonella enterica serovar Enteritidis was the most common organism isolated (4 patients). None were Salmonella enterica serovar Typhi. Initial management included aspiration and antimicrobial therapy only (3), debridement and component retention (1) and two-staged exchange (2). All four patients treated without resection failed treatment a median of 2.5 months (range 2–11) after diagnosis and required resection arthroplasty. All six patients who underwent prosthesis removal (and exchange or arthrodesis) had successful outcome with a median duration of follow-up of 11 years (range 4–21). Three of these received oral antimicrobial therapy for a median duration eight weeks (range 4–8) and three received parenteral antimicrobial therapy for a median duration of six weeks (range 4–6).

Conclusions

The increase in Salmonella outbreaks does not seem to lead to increased Salmonella PJI. PJIs due to Salmonella remain rare, and the presentation is often acute with fever. It frequently occurs in immunocompromised patients. In our patient population, removal of prosthesis with or without reimplantation, along with 4–6 weeks of effective parenteral antimicrobial therapy was most often associated with successful eradication of infection.

One-stage revision in two cases of Salmonella prosthetic hip infection

We describe two cases of prosthetic joint infection (PJI) of the hip due to Salmonella. The first patient presented with an early infection 5 d after being discharged following a total hip replacement and the second patient presented at the emergency ward with a late infection, thirteen years following a total hip replacement. Both cases occurred within one month of each other at our institution and both were successfully treated with a one-stage revision. PJI caused by Salmonella species is very rare: so far only 20 Salmonella PJIs of the hip have been described. Therefore, full consensus on the best treatment approach has not yet been reached. An aggressive two-stage approach is advised because of the virulence of Salmonella, although a limited number of successful one-stage approaches have been described as well. According to the latest guidelines, one-stage revision has comparable success rates and less morbidity compared to two-stage treatment, when selecting the right patients. In our opinion, PJI caused by Salmonella should be treated just as PJI caused by other bacteria, with consideration of the selection criteria as mentioned in several treatment guidelines. As illustrated by these two cases, one-stage revision can be successful in both early and late Salmonella PJI of the hip.

Ultrasound Detection of Salmonella Septic Arthritis in a Rheumatoid Arthritis Patient on Anti-TNF Treatment

We report a case of Salmonella septic arthritis detected by ultrasound in a 40-year-old man with rheumatoid arthritis while he was on anti–tumor necrosis factor-α monoclonal antibody certolizumab. An aspirate of his left elbow joint showed Salmonella enteritidis infection that was sensitive to ceftraixone. This was preceded by a brief episode of loose stools following a visit to the Far East. He was treated with antibiotics and made a good recovery. There have only been a few case reports of Salmonella septic arthritis in a rheumatoid arthritis patient on anti–tumor necrosis factor treatment but none previously in association with certolizumab.

Fungal peri-prosthetic joint infection after primary total knee replacement

We retrospectively reviewed 30 two-stage revision procedures in 28 patients performed for fungal peri-prosthetic joint infection (PJI) after a primary total knee replacement. Patients were followed for at least two years or until the infection recurred. The mean follow-up for patients who remained free of infection was 4.3 years (2.3 to 6.1). Overall, 17 patients were assessed as American Society of Anesthesiologists grade 3 or 4. The surgical protocol included removal of the infected implant, vigorous debridement and insertion of an articulating cement spacer. This was followed by at least six weeks of antimicrobial treatment and delayed reimplantation in all patients. The mean interval between removal of the prosthesis and reimplantation was 9.5 weeks (6 to 24). After reimplantation, patients took antifungal agents orally for a maximum of six months. Two knees became reinfected at one and two months post-operatively, respectively: one of these subsequently required arthrodesis because of uncontrolled infection. Fungal PJIs can be treated successfully by removal of all infected material, appropriate antimicrobial treatment and delayed reimplantation.

Cell invasion of poultry-associated Salmonella enterica serovar Enteritidis isolates is associated with pathogenicity, motility and proteins secreted by the type III secretion system

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a major cause of food-borne gastroenteritis in humans worldwide. Poultry and poultry products are considered the major vehicles of transmission to humans. Using cell invasiveness as a surrogate marker for pathogenicity, we tested the invasiveness of 53 poultry-associated isolates of S. Enteritidis in a well-differentiated intestinal epithelial cell model (Caco-2). The method allowed classification of the isolates into low (n = 7), medium (n = 18) and high (n = 30) invasiveness categories. Cell invasiveness of the isolates did not correlate with the presence of the virulence-associated gene spvB or the ability of the isolates to form biofilms. Testing of representative isolates with high and low invasiveness in a mouse model revealed that the former were more invasive in vivo and caused more and earlier mortalities, whereas the latter were significantly less invasive in vivo, causing few or no mortalities. Further characterization of representative isolates with low and high invasiveness showed that most of the isolates with low invasiveness had impaired motility and impaired secretion of either flagella-associated proteins (FlgK, FljB and FlgL) or type III secretion system (TTSS)-secreted proteins (SipA and SipD) encoded on Salmonella pathogenicity island-1. In addition, isolates with low invasiveness had impaired ability to invade and/or survive within chicken macrophages. These data suggest that not all isolates of S. Enteritidis recovered from poultry may be equally pathogenic, and that the pathogenicity of S. Enteritidis isolates is associated, in part, with both motility and secretion of TTSS effector proteins.