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In-hospital mortality associated with necrotizing soft tissue infection due to Vibrio vulnificus: a matched-pair cohort study
World Journal of Emergency Surgery volume 17, Article number: 28 (2022)
It remains unclear whether Vibrio vulnificus necrotizing soft tissue infection (NSTI) is associated with higher mortality compared with non-Vibrio NSTI. This study’s objective was to compare outcomes including in-hospital mortality and prognosis between patients with V. vulnificus NSTI and those with non-Vibrio NSTI.
A retrospective 1:2 matched-pair cohort study of hospitalized patients with NSTI diagnosed by surgical finding was conducted in two tertiary hospitals in southern Taiwan between January 2015 and January 2020. In-hospital outcomes (mortality, length of stay) were compared between patients with and without V. vulnificus infection. We performed multiple imputation using chained equations followed by multivariable regression analyses fitted with generalized estimating equations to account for clustering within matched pairs. All-cause in-hospital mortality and length of stay during hospitalization were compared for NSTI patients with and without V. vulnificus.
A total of 135 patients were included, 45 in V. vulnificus NSTI group and 90 in non-Vibrio group. The V. vulnificus NSTI patients had higher mortality and longer hospital stays. Multivariable logistic regression analysis revealed that V. vulnificus NSTI was significantly associated with higher in-hospital mortality compared with non-Vibrio NSTI (adjusted odds ratio = 1.52; 95% confidence interval 1.36–1.70; p < 0.01).
Vibrio vulnificus NSTI was associated with higher in-hospital mortality and longer hospital stay which may increase health care costs, suggesting that preventing V. vulnificus infection is essential.
Necrotizing soft tissue infection (NSTI) is a severe, rapidly progressive disease that is characterized by the infection of subcutaneous tissue and fascia, resulting in extensive fascial necrosis . The gold standard management for NSTI is rapid debridement and broad-spectrum antibiotics . Even under rapid and timely management, the risk of mortality and morbidity, such as amputation and multiorgan dysfunction, remains high [3,4,5]. NSTI caused by Vibrio vulnificus is a life-threatening condition with rapid progression and high mortality. It usually occurs through the injuries sustained when handling seafood, wound exposure to seawater, and ingestion of contaminated under-cooked seafood. Immunocompromised patients are also at higher risk of developing this disease [6,7,8].
Mortality from NSTI caused by gram-negative pathogens has been reported to be higher than caused by other pathogens in warm costal area ; however, it remains unclear whether mortality from V. vulnificus NSTI is higher than mortality from non-Vibrio NSTI. Only a few studies have compared mortality between V. vulnificus NSTI and non-Vibrio NSTI; one showed that the clinical features of V. vulnificus infection were more rapidly progressive and fulminant than those of the methicillin-resistant Staphylococcus aureus (MRSA) or MSSA infection , whereas another showed that the laboratory risk indicator for necrotizing fasciitis (LRINEC) score was inaccurate in necrotizing fasciitis caused by V. vulnificus. . The aim of the present study was to examine the differences in in-hospital mortality between patients with V. vulnificus NSTI and those with non-Vibrio NSTI, adjusting for comorbidities.
Material and methods
Under the approval of institutional review board, a retrospective cohort study was conducted. The medical records of patients who met the inclusion criteria of surgically proven NSTI and who received management between 2015 and 2020 in two tertiary hospitals were reviewed. Among the patients with NSTI, we selected V. vulnificus group and non-Vibrio group with 1:2 matching: For each patient in the V. vulnificus group, we identified two non-Vibrio patients of the same sex who were admitted to the same hospital in the same year and whose ages were within 5 years of the age of the V. vulnificus patient. We defined V. vulnificus NSTI group as blood culture or surgical wound culture yields V. vulnificus, or both yield V. vulnificus.
Data collection and analysis
Age, sex, vital signs in the emergency department (ED), hospital stay, the presence of comorbidities, and blood biochemistry profile were analyzed. After data collection was completed, random chart reviews were performed to ensure accuracy. We used hospital identifiers for matching to cancel out site-specific effects such as physician practice patterns and treatment outcomes. We performed multiple imputation for missing data on systolic blood pressure, body temperature, heart rate, and biochemistry analysis of blood. We replaced each missing value with a set of substituted plausible values by generating multiple datasets using the multivariate imputation by chained equations method. The following covariates were used to create these 10 complete datasets: V. vulnificus NSTI, age, sex, comorbidity, seawater or seafood contact, serum lactate, LRINEC (laboratory risk indicator for necrotizing fasciitis) sore, in-hospital death, and 30-day in-hospital death, with the assumption that data were missing at random. Estimates from these imputed datasets were combined using Rubin’s rule to obtain combined imputation estimates and standard errors. Then, using multivariable logistic regression analysis fitted with generalized estimating equations to account for the 1:2 matched-pair clustering, we examined the factors associated with all-cause in-hospital mortality.
The primary outcome of this study was all-cause in-hospital mortality. The secondary outcomes were 30-day in-hospital mortality and length of stay.
All data were analyzed using the Statistical Package for the Social Sciences software, version 20.0 (IBM Corp., Armonk, NY, USA). The chi-square test was used to compare proportions between groups. The two-sample t test was used to compare average values, and the Mann–Whitney test was used to compare the median values between groups. Using multivariable logistic regression analysis fitted with generalized estimating equations to account for the 1:2 matched-pair clustering, we examined the factors associated with all-cause in-hospital mortality. Multiple linear regression analysis fitted with generalized estimating equations.
A total of 135 patients were included, 45 in V. vulnificus NSTI group and 90 in non-Vibrio group. The mean age was 69.3 years (standard deviation [SD] = 12.7), and 66.4% of the patients were male. Table 1 shows the characteristics of patients with V. vulnificus NSTI and non-Vibrio NSTI after 1:2 matching. The V. vulnificus NSTI group tended to have hypotension, bacteremia, history of seawater or seafood contact, comorbidity with liver disease, and higher serum lactate. All-cause in-hospital mortality was 13.3% in the V. vulnificus NSTI, whereas it was 7.8% in the non-Vibrio NSTI (Table 2.). All-cause 30-day was also higher in the V. vulnificus NSTI than in the non-Vibrio group. Length of hospital stay was longer in the V. vulnificus NSTI than in the non-Vibrio group. Table 3 shows the results of the multivariable logistic regression analysis with generalized estimating equations after multiple imputation for all-cause in-hospital mortality. V. vulnificus NSTI was significantly associated with higher mortality compared with non-Vibrio group (adjusted odds ratio = 1.52; 95% confidence interval 1.36–1.70; p < 0.01). Higher mortality was significantly associated with higher serum lactate, higher LRINEC score, and with liver disease.
Vibrio vulnificus is a gram-negative marine bacterium that is usually present in warm coastal waters. The main clinical manifestations of V. vulnificus infections in humans are gastrointestinal illnesses, primary septicemia, and wound infections. The clinical course can progress rapidly by releasing hemolysins and proteases and result in hemorrhagic bullae and severe skin necrosis [10, 12, 13]. The routes of necrotizing soft tissue infection caused by V. vulnificus include wound infections while handling seafood, exposure of a preexisting wound to seawater, and ingestion of contaminated under-cooked seafood [12,13,14].
Using two tertiary hospital database in Southern Taiwan, our study showed that mortality was higher in patients with V. vulnificus NSTI than those in non-Vibrio group. In our study, in-hospital mortality among patients with V. vulnificus NSTI was 13.3%. Previous studies have reported vulnificus NSTI mortality around 10–13% [9, 15], which is comparable to our results. Mortality from NSTI caused by gram-negative or monomicrobial pathogen has been reported to be higher than caused by other pathogens. Namany et al.  found that monomicrobial disease group had a significantly higher 90-day mortality rate in addition to higher rates of in-hospital mortality, ICU admission, and vasopressor use than the polymicrobial disease group. Huang et al.  revealed that NSTI caused by monomicrobial Aeromonas spp. revealed high mortality rates, even through aggressive surgical debridement and antibacterial therapies. They all raised concern for increasing risk of monomicrobial infection and gram-negative pathogen. As comparison, the non-Vibrio group are including gram-positive, negative, and culture no growth patients, and possibly monomicrobial or polymicrobial. Mainly pathogens included Aeromonas spp., Pseudomonas, Escherichia coli, Klebsiella pneumoniae, Staphylococcus, and Streptococcus spp. (There are 39 monomicrobial gram-positive, 10 monomicrobial negative, 15 polymicrobial, and 26 culture no growth in non-Vibrio group in our data.)
In V. vulnificus NSTI, there are 17 patients with positive blood and wound culture (37.8%), 12 patients with positive blood culture (26.7%), and 16 patients with positive wound culture (35.5%). In non-Vibrio group, there are 19 patients with bacteremia (21.1%). V. vulnificus group had higher incidence of bacteremia than non-Vibrio group (64.4% vs 21.1%). Tsai et.al conducted a study about NSTI patients with V. vulnificus and methicillin-resistant Staphylococcus aureus (MRSA). The incidence of bacteremia was 65% vs 18.75%; V. vulnificus group was also higher than MRSA group . Immune-compromised and chronic liver disease (chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma) patients with V. vulnificus are more likely to develop blood stream infections [6, 18, 19]. In our study, the incidence of chronic liver disease was also higher in V. vulnificus group. Vibrio vulnificus can produce Vibrio vulnificus hemolysin/cytolysin (VVH), multifunctional autoprocessing RTX toxin, Vibrio vulnificus serine protease (VvsA), and Vibrio vulnificus protease (VVP). Both VVH and RTX toxin contribute to bacterial invasion to the blood stream and play a role in the development of hypotensive septic shock. The RTX toxin may promote the colonization at the primary infection site and cause severe tissue damage by releasing degrading cytotoxins to induce the inflammatory responses, that Vibrio vulnificus can then spread to the blood stream to result in systemic manifestations. Both VVP and VvsA are produced in the interstitial tissues of limbs and cause serious collagenolytic, hemorrhagic, or edematous skin damage in the extremities [9, 20,21,22,23]. The specific toxin of V. vulnificus may explain a relatively higher rate of blood steam infection than other pathogens. However, the comparison of Vibrio vulnificus bacteremia between NSTI and food-borne infection settings needs further studies.
Studies have shown conflicting results on the difference in mortality between patients with NSTI in subgroups. One study had shown higher mortality for NSTI patients with Aeromonas species than for those with V. vulnificus . One study had shown no significant differences of mortality between NSTI patients with V. vulnificus and Klebsiella pneumoniae . Another recent study has shown no significant differences of mortality between NSTI patients with V. vulnificus and MRSA . But few studies have focused on V. vulnificus versus non-Vibrio NSTI. In the present study, we clearly demonstrated that mortality was higher in patients with V. vulnificus than in patients with non-Vibrio NSTI. Besides, longer hospital stay may lead to higher hospitalization cost in V. vulnificus NSTI.
Our study showed that patients with hepatic dysfunction had significant associations with V. vulnificus infections and mortality. There were studies considered liver cirrhosis as risk factor with increased mortality among NSTI patients [9, 26,27,28,29]. Previous study had demonstrated that hyperlactatemia is significantly associated with in-hospital mortality in NSTI patients, even after adjusting for acidosis [30, 31]. The result was similar in the present study, even in V. vulnificus infection. Because NSTI and its rapidly progressive infection remain associated with high mortality, the LRINEC score, developed by Wong et al.  based on readily available laboratory markers, has been consistently evaluated for its efficacy in various studies. One study has been reported to be inaccurate in necrotizing fasciitis caused by V. vulnificus . However, we found the higher LRINEC score may not help early diagnosis with V. vulnificus NSTI but display a significant role with prognosis, associated with higher mortality in V. vulnificus NSTI patients.
This study still has some limitations. First, this study lacks external validation. The validity of the result still requires other studies to confirm. Second, the retrospective design of this study had its inherent limitation in data collection, such as unverified comorbidities. Third, the sample size is relatively small due to the rarity of NSTI. Fourth, the degree of liver disease in each group is not clearly stated.
In summary, adjusted in-hospital mortality was significantly higher for patients with V. vulnificus NSTI than for those with non-Vibrio NSTI in this matched-pair cohort study. Preventing V. vulnificus infection is essential. The validity of the result still needs to be confirmed by further studies.
Availability of data and materials
All the data will be available upon motivated request to the corresponding author of the present paper.
Laboratory risk indicator for necrotizing fasciitis
Methicillin-resistant Staphylococcus aureus
Necrotizing soft tissue infection
- V. vulnificus :
White blood cell
Wong C-H, Chang H-C, Pasupathy S, Khin L-W, Tan J-L, Low C-O. Necrotizing fasciitis: clinical presentation, microbiology, and determinants of mortality. J Bone Jt Surg Am. 2003;85-A:1454–60.
Headley AJ. Necrotizing soft tissue infections: a primary care review. Am Fam Phys. 2003;68:323–8.
Ozalay M, Ozkoc G, Akpinar S, Hersekli MA, Tandogan RN. Necrotizing soft-tissue infection of a limb: clinical presentation and factors related to mortality. Foot Ankle Int. 2006;27:598–605.
Roje Z, Roje Z, Matić D, Librenjak D, Dokuzović S, Varvodić J. Necrotizing fasciitis: literature review of contemporary strategies for diagnosing and management with three case reports: torso, abdominal wall, upper and lower limbs. World J Emerg Surg. 2011;6:46.
Hakkarainen TW, Kopari NM, Pham TN, Evans HL. Necrotizing soft tissue infections: review and current concepts in treatment, systems of care, and outcomes. Curr Probl Surg. 2014;51:344–62.
Chang C-P, Hsiao C-T, Lin C-N. Risk factors for mortality in the late amputation of necrotizing fasciitis: a retrospective study. World J Emerge Surg. 2018;13:1–1.
Hsu JC, Shen SH, Yang TY, Chen PH, Huang KC, Tsai YH. Necrotizing fasciitis and sepsis caused by Vibrio vulnificus and Klebsiella pneumoniae in diabetic patients. Biomed J. 2015;38:136–42.
Lee YC, Hor LI, Chiu HY, Lee JW, Shieh SJ. Prognostic factor of mortality and its clinical implications in patients with necrotizing fasciitis caused by Vibrio vulnificus. Eur J Clin Microbiol Infect Dis. 2014;33:1011–8.
Tsai YH, Huang TY, Chen JL, Hsiao CT, Kuo LT, Huang KC. Bacteriology and mortality of necrotizing fasciitis in a tertiary coastal hospital with comparing risk indicators of methicillin-resistant Staphylococcus aureus and Vibrio vulnificus infections: a prospective study. BMC Infect Dis. 2021;21(1):771.
Tsai YH, Wen-Wei Hsu R, Huang KC, Huang TJ. Comparison of necrotizing fasciitis and sepsis caused by Vibrio vulnificus and Staphylococcus aureus. J Bone Jt Surg Am. 2011;93:274–84.
Koh THB, Tan JHJ, Hong CC, Wang W, Nather A. Early clinical manifestations of vibrio necrotising fasciitis. Singap Med J. 2018;59(4):224e7.
Tsai YH, Hsu RW, Huang TJ, Hsu WH, Huang KC, Li YY, et al. Necrotizing soft tissue infections and sepsis caused by Vibrio vulnificus compared with those caused by Aeromonas species. J Bone Jt Surg Am. 2007;89:631–6.
Chuang YC, Yuan CY, Liu CY, Lan CK, Huang AH. Vibrio vulnificus infection in Taiwan: report of 28 cases and review of clinical manifestations and treatment. Clin Infect Dis. 1992;15:271–6.
Zhang XH, Austin B. Haemolysins in Vibrio species. J Appl Microbiol. 2005;98:1011–9.
Hsiao CT, Weng HH, Yuan YD, Chen CT, Chen IC. Predictors of mortality in patients with necrotizing fasciitis. Am J Emerg Med. 2008;26:170–5.
Naamany E, Shiber S, Duskin-Bitan H, Yahav D, Bishara J, Sagy I, Granat N, Drescher M. Polymicrobial and monomicrobial necrotizing soft tissue infections: comparison of clinical, laboratory, radiological, and pathological hallmarks and prognosis. A retrospective analysis. Trauma Surg Acute Care Open. 2021;6(1):e000745. https://doi.org/10.1136/tsaco-2021-000745.
Huang TY, Peng KT, Hsu WH, Hung CH, Chuang FY, Tsai YH. Independent predictors of mortality for aeromonas necrotizing fasciitis of limbs: an 18-year retrospective study. Sci Rep. 2020;10(1):7716. https://doi.org/10.1038/s41598-020-64741-7.
Kim JS, Lee EG, Chun BC. Epidemiologic characteristics and case fatality rate of Vibrio vulnificus Infection: analysis of 761 cases from 2003 to 2016 in Korea. J Korean Med Sci. 2022;37(9):e79. https://doi.org/10.3346/jkms.2022.37.e79.
Wu CJ, Chen PL, Tang HJ, et al. Incidence of Aeromonas bacteremia in southern Taiwan: vibrio and Salmonella bacteremia as comparators. J Microbiol Immunol Infect. 2014;47:145–8.
Jeong HG, Satchell KJF. Additive function of Vibrio vulnificus MARTXVv and VvhA cytolysins promotes rapid growth and epithelial tissue necrosis during intestinal infection. PLoS Pathog. 2012;8:e1002581.
Lo H, Lin J, Chen Y, et al. RTX toxin enhances the survival of Vibrio vulnificus during infection by protecting the organism from phagocytosis. J Infect Dis. 2011;203:1866–74.
Miyoshi S, Kawata K, Tomochika S, et al. The C-terminal domain promotes the hemorrhagic damage caused by Vibrio vulnificus metalloprotease. Toxicon. 2001;39:1883–6.
Elgaml A, Miyoshi SI. Regulation systems of protease and hemolysin production in Vibrio vulnificus. Microbiol Immunol. 2017;61:1–11.
Tsai YH, Huang TY, Kuo LT, Chuang PY, Hsiao CT, Huang KC. Comparison of surgical outcomes and predictors in patients with monomicrobial necrotizing fasciitis and sepsis caused by Vibrio vulnificus, Aeromonas hydrophila, and Aeromonas sobria. Surg Infect (Larchmt). 2022. https://doi.org/10.1089/sur.2021.337.
Hsu JC, Shen SH, Yang TY, Chen PH, Huang KC, Tsai YH. Necrotizing fasciitis and sepsis caused by Vibrio vulnificus and Klebsiella pneumoniae in diabetic patients. Biomed J. 2015;38(2):136–42. https://doi.org/10.4103/2319-4170.137767.
Chang CP, Hsiao CT, Fann WC. Risk factors associated with bacteremia correlated with mortality in patients with acute bacterial skin and skin structure infection. Intern Emerg Med. 2019;14(2):259–64.
Lee CY, Kuo LT, Peng KT, Hsu WH, Huang TW, Chou YC. Prognostic factors and monomicrobial necrotizing fasciitis: gram-positive versus gram-negative pathogens. BMC Infect Dis. 2011;5(11):5. https://doi.org/10.1186/1471-2334-11-5.
Wu PH, Wu KH, Hsiao CT, Wu SR, Chang CP. Utility of modified laboratory risk indicator for necrotizing fasciitis (MLRINEC) score in distinguishing necrotizing from non-necrotizing soft tissue infections. World J Emerg Surg. 2021;16(1):26. https://doi.org/10.1186/s13017-021-00373-0.
Bair MJ, Chi H, Wang WS, Hsiao YC, Chiang RA, Chang KY. Necrotizing fasciitis in southeast Taiwan: clinical features, microbiology, and prognosis. Int J Infect Dis. 2009;13(2):255–60. https://doi.org/10.1016/j.ijid.2008.04.015.
Chang CP, Fann WC, Wu SR, et al. Lactate on emergency department arrival as a predictor of in-hospital mortality in necrotizing fasciitis: a retrospective study. J Orthop Surg Res. 2019;14:73.
Wu KH, Wu PH, Chang CY, Kuo YT, Hsiao KY, Hsiao CT, Hung SK, Chang CP. Differentiating necrotizing soft tissue infections from cellulitis by soft tissue infectious fluid analysis: a pilot study. World J Emerg Surg. 2022;17(1):1. https://doi.org/10.1186/s13017-022-00404-4.
Wong CH, Khin LW, Heng KS, Tan KC, Low CO. The LRINEC (laboratory risk indicator for necrotizing fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. Crit Care Med. 2004;32(7):1535–41.
The authors thank all the participants who participated in this study.
The study was supported by Chang Gung Memorial Hospital (CORPG6E0043) (CMRPG6J0111) (CMRPG6J0112).
Ethics approval and consent to participate
The institutional review board of Chia-yi Chang Gung Memorial Hospital (IRB number: 100-4178B0C504 and 201900447B0C601) and Kaohsiung Veterans General Hospital (IRB number: VGHKS18-CT6-04) approved this retrospective study. Consent to participate was not applicable.
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Chang, CY., Wu, KH., Wu, PH. et al. In-hospital mortality associated with necrotizing soft tissue infection due to Vibrio vulnificus: a matched-pair cohort study. World J Emerg Surg 17, 28 (2022). https://doi.org/10.1186/s13017-022-00433-z
- Necrotizing soft tissue infection
- Vibrio vulnificus