Refractory Peritoneal Dialysis Peritonitis Due to Neisseria macacae: A Case Report and Review of the Literature

The Gram-negative diplococcus Neisseria macacae is a commensal bacterium of the mucosal surfaces in humans. A 52-year-old woman receiving continuous ambulatory peritoneal dialysis was admitted because of abdominal pain and turbid peritoneal fluid. N. macacae was isolated from peritoneal fluid culture and showed susceptibility to ceftriaxone. Despite appropriate antibiotics, the peritonitis was refractory, leading to the removal of the peritoneal dialysis catheter. We herein report the first case of peritoneal dialysis peritonitis caused by Neisseria macacae and review previous case reports of N. macacae infection in humans.

Deletion of the adenosine A2A receptor increases the survival rate in a mice model of polymicrobial sepsis

We aim to investigate the role of A_2A receptor in peritonitis-related sepsis by injection of a fecal solution (FS) as a model of polymicrobial infection. C57/black J6 wild-type (WT) and A_2A-deficient mice (A_2AKO) were exposed to sepsis induced by intraperitoneal injection of a FS (FS-induced peritonitis) or instead was injected with saline buffer (Sham). Survival rate and sepsis score were measured up to 48 h. The presence of bacteria in tissue homogenates was analyzed. Telemetry and speckle laser Doppler were used for systemic blood pressure and peripheral blood perfusion analysis, respectively. Histological analysis and identification of active caspase 3 were performed in selected organs, including the liver. The survival rate of A_2AKO mice exposed to FS-induced peritonitis was significantly higher, and the sepsis score was lower than their respective WT counterpart. Injection of FS increases (50 to 150 folds) the number of colonies forming units in the liver, kidney, blood, and lung in WT mice, while these effects were significantly attenuated in A_2AKO mice exposed to FS-induced peritonitis. A significant reduction in both systolic and diastolic blood pressure, as well as in the peripheral perfusion was observed in WT and A_2AKO mice exposed to FS-induced peritonitis. Although, these last effects were significantly attenuated in A_2AKO mice. Histological analysis showed a large perivascular infiltration of polymorphonuclear in the liver of WT and A_2AKO mice exposed to FS-induced peritonitis, but again, this effect was attenuated in A_2AKO mice. Finally, high expression of active caspase 3 was found only in the liver of WT mice exposed to FS-induced peritonitis. The absence of the A_2A receptor increases the survival rate in mice exposed to polymicrobial sepsis. This outcome was associated with both hemodynamic compensation and enhanced anti-bacterial response.

Seasonality of peritoneal dialysis-related peritonitis in Japan: a single-center, 10-year study

BACKGROUND

Peritonitis is one of the major complications of peritoneal dialysis (PD). Although several reports have indicated seasonality of peritonitis, the observation periods were short, and there were no reports from Japan. Therefore, the purpose of this study was to investigate the long-term seasonality of peritonitis in a single institution in Japan.

METHODS

Of 126 patients who started PD in our hospital between January 1, 2009, and December 31, 2018, 25 patients (15 men, 10 patients with diabetes) developed peritonitis with a total of 42 episodes. The median age at onset was 63 years, and the median duration from the start of PD to the onset of peritonitis was 22 months.

RESULTS

The 10-year incidence of peritonitis was 0.12 episodes per patient-year. Compared with the reference season of winter (December-February), the incidence rate ratios (95% confidence interval) for spring (March-May), summer (June-August), and autumn (September-November) were 1.75 (0.65-4.75), 1.56 (0.57-4.31), and 2.42 (0.94-6.23), respectively. In addition, no seasonality of Gram-positive and Gram-negative organisms was observed.

CONCLUSION

No seasonality was evident in the incidence of PD-related peritonitis in our hospital over a 10-year period. These findings suggest that the development of peritonitis in Japanese PD patients is not affected by seasonality.

Spontaneous bacterial peritonitis caused by Campylobacter Coli in cirrhotic patient: A rare case report (CARE-compliant)

INTRODUCTION

Spontaneous bacterial peritonitis (SBP) is a fatal infection in patients. It often happens in patients with cirrhosis, cancer or diabetes, and is caused mostly by Enterobacteriaceae. Here we report a rare case of SBP caused by Campylobacter Coli (C coli) infection, which was identified promptly by the matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and received adequate therapy sooner after.

PATIENT CONCERNS

In the present study, we reported a 46-year-old male with alcoholic liver cirrhosis (Child-Pugh class C) and type 2 diabetes mellitus presented with a 1-day history of fever and abdominal pain.

DIAGNOSIS

Based on the clinical examinations, the patient was diagnosed with SBP and the pathogen was quickly identified as C coli by the matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), a rare causative pathogen of SBP.

INTERVENTIONS

The patient received a 10-day antibiotic treatment with Ciprofloxacin 400 mg every 12 hours, and recovered successfully.

OUTCOMES

The patient had a successful treatment outcome.

CONCLUSION

The study demonstrated a new possible infectious cause of SBP by C Coli, which was rarely seen in liver cirrhosis but mostly found in immunocompromised patients. Thus, it might raise an idea of microorganism screening of broader types that might also induce SBP for immunocompromised patients.

Clostridioides difficile associated peritonitis in peritoneal dialysis patients - a case series based review of an under-recognized entity with therapeutic challenges

BACKGROUND

Initial presentation of peritoneal dialysis associated infectious peritonitis can be clinically indistinguishable from Clostridioides difficile infection (CDI) and both may demonstrate a cloudy dialysate. Empiric treatment of the former entails use of 3rd-generation cephalosporins, which could worsen CDI. We present a logical management approach of this clinical scenario providing examples of two cases with CDI associated peritonitis of varying severity where the initial picture was concerning for peritonitis and treatment for CDI resulted in successful cure.

CASE PRESENTATION

A 73-year-old male with ESRD managed with PD presented with fever, abdominal pain, leukocytosis and significant diarrhea. Cell count of the peritoneal dialysis effluent revealed 1050 WBCs/mm3 with 71% neutrophils. C. difficile PCR on the stool was positive. Patient was started on intra-peritoneal (IP) cefepime and vancomycin for treatment of the peritonitis and intravenous (IV) metronidazole and oral vancomycin for treatment of the C. difficile colitis but worsened. PD fluid culture showed no growth. He responded well to IV tigecycline, oral vancomycin and vancomycin enemas. Similarly, a 55-year-old male with ESRD with PD developed acute diarrhea and on the third day noted a cloudy effluent from his dialysis catheter. PD fluid analysis showed 1450 WBCs/mm3 with 49% neutrophils. IP cefepime and vancomycin were initiated. CT of the abdomen showed rectosigmoid colitis. C. difficile PCR on the stool was positive. IP cefepime and vancomycin were promptly discontinued. Treatment with oral vancomycin 125 mg every six hours and IV Tigecycline was initiated. PD fluid culture produced no growth. PD catheter was retained.

CONCLUSIONS

In patients presenting with diarrhea with risk factors for CDI, traditional empiric treatment of PD peritonitis may need to be reexamined as they could have detrimental effects on CDI course and patient outcomes.

Development of animal experimental model for bacterial peritonitis

Objetivo

Desarrollar un modelo de sepsis abdominal en animal de experimentación.

Material y métodos

Se utilizan ratas Sprague-Dawley®, machos de 5 semanas con pesos entre 270-280 g en el momento de la inoculación (N=39). Inicialmente se realiza un estudio piloto (N=9), distribuyéndolas en 3 grupos (3/3/3) con inóculo de 1cc de Escherichia coli ATCC 25922 intraperitoneal en concentraciones de 10⁸, 10⁹ y 10¹⁰ UFC. En un segundo estudio (N=6) con distribución en dos grupos (3/3) se utilizan 1cc una concentración de E. coli 10¹⁰ UFC que se diluyen en 10 y 15 ml de agua destilada para su inoculación. Por último se inicia un ensayo experimental con aleatorización de 24 ratas en tres grupos de tratamiento tras la infección intraperitoneal: Grupo I con suero fisiológico (N=6), Grupo II con antibiótico (ceftriaxona) (N=9), Grupo III con antibiótico más adyuvante (ceftriaxona más alicina) (N=9). Se realizan muestras microbiológicas de sangre y líquido peritoneal, así como estudio histopatológico de órganos intraperitoneales (hígado, diafragma y peritoneo).

Resultados

Se observa muerte en el 100% de las ratas infectadas con la concentración de E. coli 10¹⁰ UFC con la dilución de 15 ml de agua destilada y sin antibiótico. El hemocultivo y cultivo de líquido peritoneal es positivo a la misma cepa en todas ellas. Se observa la formación de abscesos en la superficie del hígado e infiltración por polimorfonucleares en los tejidos.

Conclusión

Se establece que la dosis letal de E. coli es 10¹⁰ UFC diluida en 15 ml agua destilada en inyección intraperitoneal.

Mucosal-Associated Invariant T Cells Redistribute to the Peritoneal Cavity During Spontaneous Bacterial Peritonitis and Contribute to Peritoneal Inflammation

BACKGROUND & AIMS

Mucosal-associated invariant T (MAIT) cells are depleted from blood in patients with advanced liver disease and show features of immune dysfunction. Because circulating MAIT cells differ from organ-resident MAIT cells, we aimed to investigate the frequency, phenotype, and function of peritoneal MAIT cells from patients with cirrhosis and spontaneous bacterial peritonitis (SBP).

METHODS

MAIT cells in blood and ascitic fluid from patients with cirrhosis were characterized using flow cytometry. Healthy individuals and noncirrhotic patients undergoing peritoneal dialysis served as controls. MAIT cell migration was studied in transwell assays. Cytokine release in response to infected ascitic fluid and bacterial products was assessed in vitro.

RESULTS

Peritoneal CD3+ CD161hi Vα7.2+ T cells had an inflammatory, tissue retention phenotype, expressing the alpha E integrin, the chemokine receptors CCR5 and CXCR3, and the activation marker CD69 at higher levels than their circulating equivalents. Seventy-seven percent bound to MR1 tetramers loaded with the pyrimidine intermediate 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil. The ratio of peritoneal to blood MAIT cell frequency increased from 1.3 in the absence of SBP to 2.6 at diagnosis and decreased by day 3. MAIT cells migrated toward infected ascitic fluid containing CCL5 and CCL20 and released cytokines in an MR1-restricted fashion. Whereas the depleted circulating MAIT cell pool displayed features of immune exhaustion, peritoneal MAIT cells remained competent producers of inflammatory cytokines in response to bacterial products. Peritoneal MAIT activation correlated with systemic inflammation, suggesting a possible link between peritoneal and systemic immunity.

CONCLUSIONS

Peritoneal MAIT cells phenotypically and functionally differ from circulating MAIT cells in decompensated cirrhosis and redistribute to the peritoneum during SBP.

Rifaximin improves survival in cirrhotic patients with refractory ascites: A real-world study

BACKGROUND

Rifaximin has been shown to reduce the incidence of hepatic encephalopathy and other complications in patients with cirrhosis. However, few studies have investigated the effect of rifaximin in cirrhotic patients with refractory ascites.

AIM

To evaluate the effects of rifaximin in the treatment of refractory ascites and to preliminarily explore its possible mechanism.

METHODS

A total of 75 cirrhotic patients with refractory ascites were enrolled in the study (50 in a rifaximin and 25 in a control group). Patients in the rifaximin group were divided into two subgroups according to the presence of spontaneous bacterial peritonitis and treatment with or without other antibiotics (19 patients treated with rifaximin and 31 patients treated with rifaximin plus intravenous antibiotics). All patients received conventional treatment for refractory ascites, while patients in the rifaximin group received oral rifaximin-α 200 mg four times daily for at least 2 wk. The ascites grade, fasting weight, liver and kidney function, and inflammatory factors in the plasma were evaluated before and after treatment. In addition, the gut microbiota was determined by metagenomics sequencing to analyse the changes in the characteristics of the gut microbiota before and after rifaximin treatment. The patients were followed for 6 mo.

RESULTS

Compared with the control group, the fasting weight of patients significantly decreased and the ascites significantly subsided after treatment with rifaximin (P = 0.011 and 0.009, respectively). The 6-mo survival rate of patients in the rifaximin group was significantly higher than that in the control group (P = 0.048). The concentration of interferon-inducible protein 10 decreased significantly in the rifaximin group compared with that in the control group (P = 0.024). The abundance of Roseburia, Haemophilus, and Prevotella was significantly reduced after rifaximin treatment, while the abundance of Lachnospiraceae_noname, Subdoligranulum, and Dorea decreased and the abundance of Coprobacillus increased after treatment with rifaximin plus intravenous antibiotics. The gene expression of virulence factors was significantly reduced after treatment in both subgroups treated with rifaximin or rifaximin plus intravenous antibiotics.

CONCLUSION

Rifaximin mitigates ascites and improves survival of cirrhotic patients with refractory ascites. A possible mechanism is that rifaximin regulates the structure and function of intestinal bacteria, thus improving the systemic inflammatory state.

Co-existence of Citrobacter freundii exacerbated Pseudomonas aeruginosa infection in vivo

The presence of bacterial species other than the pathogen at infection site can affect the progression of a bacterial infection. Based on the fact that Citrobacter freundii can coexist during Pseudomonas aeruginosa infection, this study aims to investigate the impact of the co-existing C. freundii on the pathogenesis of P. aeruginosa infection. A murine peritonitis model was used to compare the mortality rates and histopathology of P. aeruginosaPAO1 infection in the presence and absence of a C. freundii clinical isolate C9. We also investigated the intercellular interaction between PAO1 and C9 by examining pyocyanin production and comparing gene expression levels. The results demonstrate that co-infection with C9 significantly increased the mortality rate and tissue damages in PAO1 infected mice. At an inoculum of 10⁶ CFU, no mortality was observed in the C9 infected group at three days post-infection, whereas the mortality rate in the PAO1-C9 co-infection group was 64%, compared with 24% in the PAO1 infected group. Pyocyanin production in P. aeruginosa PAO1 increased 8 folds approximately in the presence of C. freundii C9, and operons associated with phenazine synthesis, phzA1 and phzA2, were also upregulated. Disruption of the phzA1 and phzA2 eliminated the exacerbated pathogenicity in the co-infection group, indicating that the elevated pyocyanin production was the main contributing factor. The results suggest that co-existing C. freundii during P. aeruginosa infection can exacerbate the pathogenicity, which may have significant implications in patients infected with these bacteria.

Continuous ambulatory peritoneal dialysis peritonitis: Microbiology and outcomes

Context

Continuous ambulatory peritoneal dialysis (CAPD) is now a preferred mode of the treatment in patients with end-stage renal disease, but peritonitis remains to be a shortcoming of CAPD. High-culture negativity, emerging drug resistance and peritoneal dialysis (PD)-related morbidity and mortality have been a challenge to tackle.

Aims

The present study was taken up to compare the the various culture methods and to identify the spectrum of organisms causing CAPD peritonitis and their outcome.

Settings and Design

A prospective, observational, cross-sectional study was conducted at a tertiary care teaching hospital in Hyderabad over a period of 1 year.

Subjects and Methods

Dialysate fluid from 100 episodes of clinically suspected peritonitis in 75 patients was processed by conventional centrifuging, water lysis, direct inoculation and addition of centrifuged pellet into brain-heart infusion broth and by automated blood culture system. Identification and antibiotic susceptibility of organisms was done, and the outcome of PD-related peritonitis was analysed.

Statistical Analysis Used

The categorical data and continuous data were analysed using the Chi-square test and Student's t-test, respectively. P < 0.05 was considered statistically significant.

Results

Of the 100 PD fluids, 87 were culture positive. Automated blood culture systems detected 87 episodes, whereas conventional centrifuge method detected only 53 episodes (P = 0.00001). Peritonitis due to Gram-negative organisms (62.3%) was higher than that of Gram-positive peritonitis (31.1%) and fungi (6.4%). Nineteen per cent episodes were constituted by relapse (9), refractory (4), recurrent (4) and repeat (2) peritonitis. Outcomes were analysed as recovery (77%), catheter removal (15%) and death (2.6%).

Conclusions

Direct inoculation of peritoneal fluid into automated blood culture bottles increases the positivity rate and also aids in the early detection of CAPD peritonitis, helping reduce morbidity and mortality of PD patients.

Prophylactic potential of cytolethal distending toxin B (CdtB) subunit of typhoid toxin against Typhoid fever

Typhoid fever caused by Salmonella enterica serovar Typhi (S.Typhi) continues to be a major problem, especially in developing countries. Due to the rapid emergence of multi-drug-resistant (MDR) strains, which limits the efficacy of conventional antibiotics as well as problems associated with the existing vaccines, efforts are being made to develop effective prophylactic agents. CdtB subunit of typhoid toxin was selected for assessing its vaccine potential due to its high conservation throughout the Typhi strains. In-vitro assessment of DNase activity of cloned and purified CdtB protein showed a significant decrease in the band intensity of DNA. The measure of metabolic activity and morphological alterations assessed using different cell lines in the presence of CdtB protein showed no significant signs of toxicity. These observations were further strengthened by cell cycle analysis, assessed by flow cytometry. Keeping these observations in mind, the immunoprotective potential of CdtB was assessed using S.Typhi induced mouse peritonitis model. A significant titer of IgG antibodies (>128000) against CdtB protein was recorded in the immunized mice by enzyme-linked immunosorbent assay (ELISA), which was also validated by immunoblotting. Active immunization with the protein protected 75% mice against a lethal dose of S.Typhi Ty2. The data indicated a significant (up to 5 log) reduction in the bacterial load in the spleen and liver of immunized-infected mice compared to control (unimmunized-infected) mice which might have resulted in the modulation of histoarchitecture of spleen and liver and the levels of cytokines (IL-6, TNF-α and IL-10) production; thereby indicating the effectiveness of the subunit. The observations deduced from the study give the proof of concept of immunogenic potential of protein. However, further studies involving the immunoreactivity of CdtB with the statistically significant number of sera samples obtained from the human patients would be helpful in establishing the relevance of CdtB protein in humans and for making the strategies to develop it as an effective vaccine candidate.

Fungal Isolates in Peritoneal Fluid Culture Do Not Impact Peri-Operative Outcomes of Peptic Ulcer Perforation

Background: Fungal isolates from peritoneal fluid sampling in patients with perforated peptic ulcer (PPU) is not uncommon and its management unclear. This study aims to evaluate whether the presence of fungus in peritoneal fluid cultures is a predictor of morbidity and mortality after laparotomy for PPU. Method: This is a single-center retrospective study including adult patients with perforated gastric and duodenal ulcers over a 10-year period (January 2004 to January 2014). Evaluation of predictors contributing to fungal growth was conducted using multiple logistic regression analysis. Operative factors and 30-day mortality and morbidity outcomes were compared against fungal growth using a multivariable generalized linear mixed model analysis. Results: The median age was 58 (interquartile range [IQR] 44-70) years with 110 (20.3%) females. In addition to hypertension and hyperlipidemia, diabetes mellitus (13.5%), ischemic heart disease (2.6%), and heart failure (2.4%) were common. Fungus was cultured from peritoneal fluid in 209 (38.6%) patients. Median American Society of Anesthesiology (ASA) score was 2 (IQR 2-3) and median Mannheim peritonitis index (MPI) score was 15 (IQR 10-20). Free air was detected in 323 (59.6%) patients and 52 (9.6%) patients had gastrectomy. Median length of stay was 7 (IQR 6-11) days. All-cause complications were seen in 53 (9.8%) patients, of whom 37 patients (6.8%) developed intra-abdominal collection, 20 patients (3.7%) had anastomotic leakage, and 12 patients (2.2%) required repeat operation. Thirty-day mortality was seen in 47 (8.7%) patients. Multivariable analysis showed age (median age, 64; IQR 53-74) as a predictor of fungal growth (p < 0.001) but fungal growth not a predictor of adverse peri-operative outcomes. Conclusion: Fungal isolates in peritoneal fluid cultures are more likely to occur in older patients who have PPU. Presence of fungal isolates does not impact peri-operative outcomes.

T6SS and ExoA of flesh-eating Aeromonas hydrophila in peritonitis and necrotizing fasciitis during mono- and polymicrobial infections

An earlier report described a human case of necrotizing fasciitis (NF) caused by mixed infection with 4 Aeromonas hydrophila strains (NF1-NF4). While the NF2, NF3, and NF4 strains were clonal and possessed exotoxin A (ExoA), the NF1 strain was determined to be phylogenetically distinct, harboring a unique type 6 secretion system (T6SS) effector (TseC). During NF1 and NF2 mixed infection, only NF1 disseminated, while NF2 was rapidly killed by a contact-dependent mechanism and macrophage phagocytosis, as was demonstrated by using in vitro models. To confirm these findings, we developed 2 NF1 mutants (NF1ΔtseC and NF1ΔvasK); vasK encodes an essential T6SS structural component. NF1 VasK and TseC were proven to be involved in contact-dependent killing of NF2 in vitro, as well as in its elimination at the intramuscular injection site in vivo during mixed infection, with overall reduced mouse mortality. ExoA was shown to have an important role in NF by both NF1-exoA (with cis exoA) and NF2 during monomicrobial infection. However, the contribution of ExoA was more important for NF2 than NF1 in the murine peritonitis model. The NF2∆exoA mutant did not significantly alter animal mortality or NF1 dissemination during mixed infection in the NF model, suggesting that the ExoA activity was significant at the injection site. Immunization of mice to ExoA protected animals from NF2 monomicrobial challenge, but not from polymicrobial infection because of NF2 clearance. This study clarified the roles of T6SS and ExoA in pathogenesis caused by A. hydrophila NF strains in both mouse peritonitis and NF models in monomicrobial and polymicrobial infections.

[Purulent peritonitis due to gonococcal infection]

BACKGROUND A Neisseria gonorrhoea infection is one of the most common sexually transmitted diseases and can present both urogenitally and extragenitally. CASE DESCRIPTION A 55-year-old woman presented at the emergency room with general malaise, abdominal pain and fever. Despite extensive surgical, gynaecological and radiological investigations no clear cause could initially be found. She was subsequently admitted to the surgical unit for observation. During the admission period the patient developed diffuse peritonitis and her infection parameters were rising. Diagnostic laparoscopy revealed extensive terminal ileitis with a reactive infiltrate of the uterine fundus and purulent peritonitis. A PCR test of the abdominal exudate was strongly positive for Neisseria gonorrhoeae, but cultures remained negative. Following an 8-day course of antibiotic treatment with intravenous ceftriaxone, the patient recovered from her symptoms. CONCLUSION Terminal ileitis with peritonitis is an unusual extragenital manifestation of a gonococcal infection. In order to make a diagnosis, surgical exploration with cultures is sometimes indicated.

[Usefulness of test strips for early diagnosis of spontaneous bacterial peritonitis in cirrhotic patients with ascites]

INTRODUCTION

Spontaneous bacterial peritonitis requires an early diagnosis to start antibiotic therapy. The ideal diagnostic study is the cytochemical of ascites fluid, which can be expensive, delayed and of limited availability in primary health care centers.

OBJECTIVE

Evaluate the usefulness and diagnostic accuracy of Multistix 10SG test strips for the diagnosis of spontaneous bacterial peritonitis in cirrhotic patients with ascites.

MATERIALS AND METHODS

Observational descriptive study of diagnostic test in cirrhotic patients with ascites. The leukocyte count of ascites fluid was determined by the colorimetric scale of the Multistix 10SG test strip and compared with the gold standard for diagnosis (polymorphonuclear ≥ 250 cells / mm³).

RESULTS

Of 174 patients with ascites (51.7% women, average age 59 years) 30 were diagnosed with spontaneous bacterial peritonitis. With a grade ++ cut-off point, the test strip had sensitivity 73.3%, specificity 96.5%, positive predictive value 81.4%, negative predictive value 94.5%, positive likelihood ratio 21.2 and negative likelihood ratio of 0.27.

CONCLUSIONS

The test strips have adequate specificity and negative predictive value, being a low cost tool, simple use, quick interpretation and easy access, to support the decision not to start an antibiotic in patients with ascites and suspected spontaneous bacterial peritonitis. Due to their low sensitivity they do not replace the cytochemical study as the test of choice for the definitive diagnosis, but it is useful for optimizing the initial approach of these patients.

Anti-inflammatory activity of β-caryophyllene combined with docosahexaenoic acid in a model of sepsis induced by Staphylococcus aureus in mice

BACKGROUND

Sepsis is a set of serious organic manifestations caused by an infection, whose progression culminates in exacerbated inflammation and oxidative stress, poor prognosis, and high hospital costs. Antioxidants used against sepsis have been evaluated, including essential oils such as β-caryophyllene (BCP), and polyunsaturated fatty acids, such as docosahexaenoic acid (DHA). The aim of this study was to evaluate the anti-inflammatory activity of the association of these two compounds.

RESULTS

Treatment with BCP-DHA, at a dose of 200 μL/animal, significantly inhibited the migration of neutrophils in a Cg-induced peritonitis model. After Staphylococcus aureus infection, in the groups treated with BCP-DHA there was a significant decrease in the total and differential count of leukocytes, increased expression of cytokines TNF-α and IFN-γ in treated groups, an increase of IL-4 and IL-5 in B/D and B/D + SA groups, and an augmentation of IL-6 and IL-12 groups in B/D + SA groups. Histological and bacterial analysis revealed lower neutrophil migration and lower bacterial load in the infected and treated groups.

CONCLUSION

In general, the BCP-DHA association presented anti-inflammatory activity against two different models of acute inflammation and infection, showing promising potential as a therapeutic adjuvant in sepsis. © 2019 Society of Chemical Industry.

Model for End-Stage Liver Disease Score Predicts Development of First Episode of Spontaneous Bacterial Peritonitis in Patients With Cirrhosis

OBJECTIVE

To examine whether baseline model for end-stage liver disease (MELD) score in patients with cirrhosis and ascites predicts the future development of first spontaneous bacterial peritonitis (SBP) episode.

METHODS

A retrospective case-control study was performed at three academic centers to select patients admitted with first SBP episode (cases) and those with ascites admitted for decompensation without SBP (controls). Medical records from these centers were reviewed between January 1, 2008, and December 31, 2013. Cases and controls were matched (1:2) for age, sex, and race. Conditional logistic recession models were built to determine whether baseline MELD score (within a month before hospitalization) predicts first SBP episode.

RESULTS

Of 697 patients (308, 230, and 159 from centers A, B, and C, respectively), cases and controls were matched in 94%, 89%, and 100% at three respective centers. In the pooled sample, probability of SBP was 11%, 31%, 71%, and 93% at baseline MELD scores less than or equal to 10, from 11 to 20, from 21 to 30, and greater than 30, respectively. Compared with MELD score less than or equal to 10, patients with MELD scores from 11 to 20, 21 to 30, and greater than 30 had six- (3- to 11-), 29- (12- to 69-), and 115- (22- to 598-) folds (95% CI) risk of SBP, respectively. Based on different MELD score cutoff points, MELD score greater than 17 was most accurate in predicting SBP occurrence. Analyzing 315 patients (152 cases) with available data on ascitic fluid protein level controlling for age, sex, and center, MELD score but not ascitic fluid protein associated with first SBP episode with respective odds ratios of 1.20 (1.14 to 1.26) and 0.88 (0.70 to 1.11).

CONCLUSION

Baseline MELD score predicts first SBP episode in patients with cirrhosis and ascites.

Enterococcus faecalis Escapes Complement-Mediated Killing via Recruitment of Complement Factor H

BACKGROUND

Enterococcus faecalis is considered to be the most important species of enterococci responsible for blood stream infections in critically ill patients. In blood, the complement system is activated via the classical pathway (CP), the lectin pathway (LP), or the alternative pathway (AP), and it plays a critical role in opsonophagocytosis of bacteria including E faecalis.

METHODS

In a mouse model of enterococcus peritonitis, BALB-C mice were challenged with a high dose of E faecalis 12 hours after intraperitoneal administration of anti-Factor H (FH) antibodies or isotype control. Four hours later, control mice developed higher bacterial burden in blood and organs compared with mice treated with anti-FH antibodies.

RESULTS

We demonstrate that complement recognition molecules C1q, CL-11, and murine ficolin-A bind the enterococcus and drive the CP and the LP in human and mouse. We further describe that E faecalis evades the AP by recruitment of FH on its surface. Our results show a strong C3b deposition on E faecalis via both the CP and the LP but not through the AP.

CONCLUSIONS

These findings indicate that E faecalis avoids the complement phagocytosis by the AP via sequestering complement FH from the host blood.

NK Cells in Ascites From Liver Disease Patients Display a Particular Phenotype and Take Part in Antibacterial Immune Response

Background and Aims: Ascites and spontaneous bacterial peritonitis (SBP) are frequent complications of liver cirrhosis. In spite of the clinical impact, knowledge about ascites as an immune cell compartment in liver disease is limited. Therefore, we analyzed NK cells in blood, ascites, and liver. Methods: Mononuclear cells from blood, ascites, and liver explants of patients with advanced liver disease were extracted by density gradient centrifugation. Phenotyping and analysis of functional responses were carried out using flow cytometry. Migratory potential was investigated with transwell chamber assays. NK cell metabolism was assessed by Seahorse technology. Results: NK cell frequency was increased in uninfected ascites compared to blood, but not to liver. Ascites NK cells were predominantly CD16positive. CD56bright ascites NK cells did not share the typical phenotype of their liver counterparts. In contrast to the inhibitory receptor NKG2A, expression of the activating receptor NKG2D was decreased on ascites and liver CD16positive NK cells. Ascites NK cells expressed higher levels of CXCR3 than blood or liver NK cells, corresponding to increased ascites levels of CXCL10. Blood NK cells migrated toward ascites. Stimulation of mononuclear cells with Escherichia coli led to downregulation of NKG2D expression and IL-12 and IL-18 mediated secretion of interferon-γ by ascites and liver, but not blood NK cells. In-vivo, ascites NK cells expressed higher levels of the activation marker CD69 and lower levels of NKG2D during SBP compared to uninfected ascites. Conclusion: Ascites NK cells display a particular phenotype and are implicated in local immune defense against translocating bacteria.

Sustained impact of nosocomial-acquired spontaneous bacterial peritonitis in different stages of decompensated liver cirrhosis

Background & aims

Bacterial infections, in particular a spontaneous bacterial peritonitis (SBP), are a major threat in patients with liver cirrhosis. Recently, it has been shown that the impact on mortality might be underestimated by established risk-scores. Onset of infection was suggested to define a distinct stage of cirrhosis. However, it remains unclear whether all stages of decompensated cirrhosis are equally affected. Moreover, if there is such a distinct stage, it must be determined whether it is reversible after the infection has resolved.

In this study we aimed to further analyze the impact of a current as well as a resolved SBP in different stages of decompensated liver cirrhosis.

Methods

A number of 579 patients with liver cirrhosis and ascites were included. MELD-score was used to determine the stage of liver disease. Low (<15), intermediate (15–25) and high (>25) MELD-groups were compared. Patients were followed up for 90 days. Primary endpoint was overall mortality. Statistical analyses were performed using the log-rank test, Cox regression and competing risk analysis.

Results

Mortality was significantly higher in patients with nosocomial-acquired SBP (nSBP) compared to patients without SBP (p<0.001;HR = 2.05). However, the most prominent difference in mortality was documented in the intermediate MELD-group (nSBP: p = 0.02;HR = 2.10). Importantly, mortality in nSBP patients remained increased even after the initial nSBP episode had resolved (p<0.01;HR = 1.90). Again, this was only significant in those with intermediate MELD-scores (p = 0.02;HR = 2.28). While a current as well as a resolved nSBP were significantly linked to a higher mortality, neither of them did increase the likelihood for liver transplantation.

Conclusions

Development of nSBP is independently associated with increased mortality supporting the concept of a distinct status of cirrhosis. Importantly, the prognosis remains unfavorable even after resolution of nSBP. This could be particularly relevant for patients with intermediate MELD-scores, who have limited chances for a donor liver.

Demographic characteristics and outcomes of continuous ambulatory peritoneal dialysis related peritonitis in Miri General Hospital, Malaysia

INTRODUCTION

Sarawak has a population that is geographically and characteristically widely varied. In this study we aimed to determine the demographic characteristics of our patient population who undergo continuous ambulatory peritoneal dialysis (CAPD) and to study the incidence, the microbiology and the outcome of CAPD peritonitis.

METHODS

A retrospective record review of all CAPD patients on follow-up at the Miri Hospital, Sarawak, Malaysia from 2014 until 2017 was done.

RESULTS AND DISCUSSION

During the 4-year period, the overall peritonitis rate was 0.184 episodes per patient-year. Gram-positive and gram-negative bacteria each constituted one-third of the peritonitis; fungi (2.6%), Mycobacterium tuberculosis (MTB) (5.3%), polymicrobial (2.6%) and sterile culture (26.3%). The most commonly isolated gram-positive bacteria were coagulase-negative Staphylococcus. Our peritonitis rate is comparable to that of other centres i.e., Japan 0.195 and Indonesia 0.25. In comparison, countries like India (0.41), Korea (0.40) and Singapore (0.59) had relatively higher rate of PD-associated peritonitis. Two tuberculosis peritonitis patients died. The rate of catheter removal was approximately 20%. Gram-negative bacteria and MTB have a higher risk of catheter loss. About one-fifth used rainwater to clean their CAPD exit site. Out of this group, 33% did not boil the rainwater prior to usage.

CONCLUSION

Patient's characteristics and microbial susceptibility vary in different places of practice. The high rates of culture-negative peritonitis and high mortality risks associated with TB peritonitis warrant special attention. In patients with refractory peritonitis, early catheter removal is warranted in order to reduce mortality and minimize damage to peritoneal membrane.

Prevalence and Predictors of Third-Generation Cephalosporin Resistance in the Empirical Treatment of Spontaneous Bacterial Peritonitis

OBJECTIVE

To better characterize the changing patterns of spontaneous bacterial peritonitis (SBP) in a tertiary academic center in the United States by identifying the prevalence of gram-positive organisms and cephalosporin resistance along with predictors of mortality and antibiotic drug resistance.

PATIENTS AND METHODS

We reviewed 481 consecutive patients with SBP at Mayo Clinic in Rochester, Minnesota, from January 1, 2005, through December 31, 2016. Data on comorbid conditions, etiology of cirrhosis, factors predisposing to infection, and antimicrobial and antibiotic drug use were collected.

RESULTS

We identified 96 patients (20%) with culture-positive SBP requiring treatment (median age, 60 years; age range, 22-87 years; 44% men). Gram-positive organisms account for more than half of the cases. Overall resistance to third-generation cephalosporins was 10% (n=10). Risk factors for third-generation cephalosporin resistance include nosocomial acquisition, recent antibiotic drug use, and hepatocellular carcinoma. The negative predictive value for antibiotic drug resistance in the present model was 96% (70 of 73). Overall mortality at 30 and 90 days was 23% and 37%, respectively.

CONCLUSION

These findings support the recent observation of a rising prevalence of gram-positive organisms in SBP. Despite the changing pattern, third-generation cephalosporins seem to provide adequate empirical treatment in patients with community-acquired and health care-associated SBP without hepatocellular carcinoma.

Draft genome sequence of a clinical Acinetobacter baumannii isolate of new sequence type ST1688 from Saudi Arabia

OBJECTIVES

Acinetobacter baumannii has emerged as a prevalent multidrug-resistant nosocomial pathogen worldwide. Here we report the draft genome sequence of A. baumannii strain Ab174 isolated from a neonatal patient diagnosed with acute peritonitis.

METHODS

The draft genome sequence of A. baumannii Ab174 was determined using a MiSeq platform (Illumina Inc., San Diego, CA) using v.3, 2×30-bp chemistry. Genomic assembly was performed using SPAdes 3.9 algorithm.

RESULTS

The draft genome of A. baumannii Ab174 is 3 747 065bp in length and was classified as a new sequence type (ST1688). The genome of A. baumannii Ab174 has a G+C content of 39% and harbours two plasmids. The antimicrobial resistance gene bla_ADC-25 and the virulence factor gene for penicillin-binding protein G (pbpG) as well as 17 genomic islands and 14 insertion sequences were identified in the genome of A. baumannii Ab174.

CONCLUSION

The genome sequence of A. baumannii strain Ab174 can be used as a reference sequence for the new ST1688. These data will facilitate further understanding of genomic variation in isolates from different geographical regions.

Evaluation of Platensimycin and Platensimycin-Inspired Thioether Analogues against Methicillin-Resistant Staphylococcus aureus in Topical and Systemic Infection Mouse Models

Staphylococcus aureus is one of the most common pathogens causing hospital-acquired and community-acquired infections. Methicillin-resistant S. aureus (MRSA)-formed biofilms in wounds are difficult to treat with conventional antibiotics. By targeting FabB/FabF of bacterial fatty acid synthases, platensimycin (PTM) was discovered to act as a promising natural antibiotic against MRSA infections. In this study, PTM and its previously synthesized sulfur-Michael derivative PTM-2t could reduce over 95% biofilm formation by S. aureus ATCC 29213 when used at 2 μg/mL in vitro. Topical application of ointments containing PTM or PTM-2t (2 × 4 mg/day/mouse) was successfully used to treat MRSA infections in a BABL/c mouse burn wound model. As a potential prodrug lead, PTM-2t showed improved in vivo efficacy in a mouse peritonitis model compared with PTM. Our study suggests that PTM and its analogue may be used topically or locally to treat bacterial infections. In addition, the use of prodrug strategies might be instrumental to improve the poor pharmacokinetic properties of PTM.

Comparison of the effectiveness of caspofungin and liposomal amphotericin-B for the treatment of C. tropicalis-induced peritonitis in mice

In order to compare the effectiveness of liposomal amphotericin B (LAB) and caspofungin monotherapy in Candida tropicalis-induced peritonitis in an experimental mice model 56 healthy male BALB/c mice (10-12 weeks; 20-25 g) were divided into groups and C. tropicalis strains were intraperitoneally (IP) inoculated into mice groups except the control group. After the injection, three doses of LAB (0.5, 1.0, 2.0 mg/kg/day) and caspofungin (1.0, 2.0, 5.0 mg/kg/day) were administered to groups for five consecutive days, starting 48-h post-infection. The mice were then followed up for 14 days and killed by cervical dislocation. When their peritoneal fluid was examined, the difference in fungal growth between the treatment group and control group was significant (p <0.05). Evaluation of the treatment groups revealed that fungal growth decreased with increasing dose of the antifungal agent (p >0.05). There was no dose-related difference from mice which received LAB or those which received caspofungin in our experimental model. During our study, no death was detected despite the similar injection doses compared with other studies using Candida species. The results of this study suggest that C. tropicalis could have lower virulence, perhaps limited by natural immunity, and causes mortality at much higher doses.