Translocation of coagulase-negative bacterial staphylococci in rats following intestinal ischemia-reperfusion injury

Congestive ischemic colitis successfully treated with anti-inflammatory therapy: A case report

BACKGROUND

Congestive ischemic colitis is a rare subtype of ischemic colitis with an unknown pathophysiology. Excluding conservative management, such as fasting, no established treatment exists; therefore, surgical intervention should be considered in some cases if symptoms worsen. Current literature suggests that anti-inflammatory agents may effectively treat congestive ischemic colitis.

CASE SUMMARY

We present the case of a 68-year-old female patient who underwent laparoscopic left hemicolectomy for transverse colon cancer 3 years ago. Postoperatively, follow-up included an annual colonoscopy and abdominal computed tomography (CT) at a local clinic. However, progressive erythema and edema of the sigmoid colon were observed 1 year postoperatively. Upon admission to our hospital, she complained of abdominal pain and diarrhea. Abdominal CT showed thickening of the sigmoid colon walls, and colonoscopy revealed erythema, edema, and multiple ulcers with exudate in the sigmoid colon. CT angiography showed engorgement of the sigmoid vasa recta without any vascular abnormalities. The diagnosis was congestive ischemic colitis, and we treated the patient with anti-inflammatory agents. After 2 mo of glucocorticoid therapy (20 mg once daily) and 7 mo of 5-aminosalicylate therapy (1 g twice daily), the ulcers completely healed. She has not experienced any recurrence for 2 years.

CONCLUSION

Anti-inflammatory therapy, specifically glucocorticoids and 5-aminosalicylate, has demonstrated promising efficacy and introduces potential novel treatment options for congestive ischemic colitis.

Reducing catheter related bloodstream infection risk of infant with a prophylactic antibiotic therapy before removing peripherally inserted central catheter: A retrospective study

PURPOSE

This study examined the efficacy of prescribing antibiotics, specifically a single dose of vancomycin, in reducing the incidence of culture-positive and culture-negative sepsis prior to the removal of peripherally inserted central catheters (PICCs).

MATERIALS AND METHODS

We retrospectively reviewed charts of infants who had PICCs in a tertiary level hospital during the period from 2010 to 2019. The incidence of post-catheter removal clinical sepsis between the groups with or without antibiotics was compared. The antibiotic group was defined by receiving a single dose of vancomycin or any other antibiotic prior to line removal.

RESULTS

We enrolled 585 PICC removal episodes in 546 infants for analysis. Antibiotics were given prior to removal in 257 cases (43.9%) and not given prior to removal in 328 cases (56.1%). There were 13 episodes of post-catheter removal clinical sepsis detected within 72 h (2.2%), 2 of which were culture-positive (0.3%). A 9.3-fold decrease in the odds for clinical sepsis was observed in the antibiotic group (p = 0.01). The incidence of post-catheter removal sepsis was decreased by a single prophylactic dose of vancomycin (p = 0.02), whereas the use of other antibiotics showed no effect (p = 0.35). Logistic regression analysis demonstrated that comorbidities with gastrointestinal diseases (p = 0.01), PICC insertion sites in the scalp and neck (p = 0.04), and no vancomycin administration prior to line removal (p = 0.02) were independent risk factors for subsequent clinical sepsis.

CONCLUSION

A single prophylactic dose of vancomycin prior to PICC line removal might reduce clinical sepsis events in infants.

Bad blood: ischemic conditions of the large bowel

PURPOSE OF REVIEW

Colon ischemia is the most common form of intestinal ischemic injury and is seen frequently in an elderly population. This disease is usually self-limited, and many causes have been identified. The recent literature has focused on estimates of prognosis, triaging appropriate level of care, and identification of optimal treatments. In this review, we will address our current understanding of colon ischemia including epidemiology, pathophysiology, segmental distribution, presentation, diagnosis, and management.

RECENT FINDINGS

Research has recently been focused on factors associated with poor outcome. The medical comorbidities identified include chronic obstructive pulmonary disease (COPD), hepatic cirrhosis, and chronic aspirin use. Serological markers are noninvasive tools that can triage severity. Recent studies have shown procalcitonin, C-reactive protein, D-dimer, and neutrophil counts can help predict those at greatest risk for poor outcome. The timing of colonoscopy relative to symptomatic onset also can help predict severity. Early colonoscopy allows for quicker identification of ischemic stigmata, reducing the chance of misdiagnosis and potentially unnecessary and harmful treatment. The treatment of colon ischemia has classically been conservative with antimicrobials reserved for those with moderate or severe disease. Recent retrospective analysis calls into question the utility of antibiotics in the treatment of colon ischemia, although the data is not convincing enough to advise against antimicrobial treatment in patients with severe and fulminant disease.

SUMMARY

It is an exciting time for research focused on colon ischemia. With an improved knowledge, awareness of associated risk factors and predictors of severity, clinicians now have enhanced clinical tools to diagnose and triage patients earlier in the disease. This should help institute prompt and appropriate therapies ultimately improving outcomes.

Diagnostic methods and drug therapies in patients with ischemic colitis

PURPOSE

Ischemic colitis (IC) is the most prevalent ischemic injury of thegastrointestinal tract. Clinical features of IC such as acute abdominal pain, hematochezia,and diarrhea are similar to those of acute mesenteric ischemia, inflammatorybowel disease, or infectious bowel disease, and their relative ambiguity candelay diagnosis and treatment. To comprehensively detail the current state ofdiagnostic methods and available drug therapies for detecting and treating IC,this review aims to provide a concise and practical summary of thecorresponding literature.

METHODS

PubMed and Cochrane Library were searched toretrieve all published studies reporting the diagnostic methods and drugtherapies in patients with ischemic colitis. The search strategy of drugtherapy includes human and animal data.

RESULTS

Colonoscopy combined with histopathologicalbiopsy is the standard of diagnosis for the IC. Most patients respond well tothe conservative treatment, and surgical consultation is needed when conservativetreatment is ineffective. Studies of potential drug therapy have beendeveloped, including phosphodiesterase type 5 inhibitors, pentoxifylline,rebamipide, prostaglandin E1, and polydeoxyribonucleotide.

CONCLUSION

Accurate diagnoses and effective treatmentshave helped reduce the mortality rate and improve prognoses for patientsafflicted with IC, and corresponding drug therapies have been constantlyupdated as new research has emerged.

Coagulase-Negative Staphylococci Contained in Gut Microbiota as a Primary Source of Sepsis in Low- and Very Low Birth Weight Neonates

Background: There are only a few reports in the literature about translocation of coagulase-negative staphylococci (CoNS) as a primary cause of sepsis in neonates, although CoNS are among a short list of “translocating” bacteria when present in abundance. Methods: 468 blood samples, 119 stool samples, and 8 catheter tips, from 311 neonates, were tested for presence of microorganisms. CoNS strains isolated from the blood and stool or from blood and catheter tip of the same newborn at approximately the same time were paired and typed with PFGE (Pulse-Field Gel Electrophoresis) method. The strains were then tested for the presence of adherence genes and biofilm formation. Results: The strains with identical PFGE profiles in comparison to those with non-identical profiles differed in terms of the pattern of the virulence genes and showed a lack of the genes related to adherence, but more often presence of IS256, which is related to virulence. They also were phenotypically unable to adhere to intestinal Caco2 cells. Conclusions: A considerable proportion of CoNS strains isolated from bloodstream of VLBW/LWB neonates was identical to the strains isolated from faeces of the same neonates at the same time. These observations may offer indirect evidence indicating that at least some CoNS can translocate from the gastrointestinal tract of the premature neonates into the bloodstream and thus cause generalized infection.

The Uncertain Effect of Antimicrobial Therapy in the Treatment of Patients with Ischemic Colitis

Although antimicrobial therapy is recommended for patients with moderate or severe ischemic colitis, its beneficial effects are unclear. In the present study, the role of antimicrobial therapy in the treatment of ischemic colitis was investigated. Patients with ischemic colitis were retrospectively identified between January 2004 and June 2019. The characteristics and outcomes of patients who received antibiotics (antibiotics group) and those who did not (no-antibiotics group) were compared. Clinical outcomes included death, surgery, and readmission within 30 days, fasting duration, and hospital stay. Data from 186 patients were analyzed; 122 patients were in the antibiotics group and 64 in the no-antibiotics group. Composite outcome of death, surgery, and readmission within 30 days occurred in 3.3% of patients in the antibiotics group and 3.1% of patients in the no-antibiotics group (p > 0.999). Fasting duration was not significantly different between the two groups (median days, 4.0 vs. 4.0, p = 0.253). However, hospital stays were longer in the antibiotics group than in the no-antibiotics group (median days, 9.0 vs. 7.0, p = 0.043). In patients with ischemic colitis, there was no statistically significant difference in the incidence of death, surgery, and readmission within 30 days between patients who received antibiotics and those who did not receive antibiotics.

Beyond sepsis: Staphylococcus epidermidis is an underestimated but significant contributor to neonatal morbidity

Staphylococcus epidermidis accounts for the majority of cases of neonatal sepsis. Moreover, it has been demonstrated to be associated with neonatal morbidities, such as bronchopulmonary dysplasia (BPD), white matter injury (WMI), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP), which affect short-term and long-term neonatal outcome. Imbalanced inflammation has been considered to be a major underlying mechanism of each entity. Conventionally regarded as a harmless commensal on human skin, S. epidermidis has received less attention than its more virulent relative Staphylococcus aureus. Particularities of neonatal innate immunity and nosocomial environmental factors, however, may contribute to the emergence of S. epidermidis as a significant nosocomial pathogen. Neonatal host response to S. epidermidis sepsis has not been fully elucidated. Evidence is emerging regarding the implication of S. epidermidis sepsis in the pathogenesis of neonatal inflammatory diseases. This review focuses on the interplay among S. epidermidis, neonatal innate immunity and inflammation-driven organ injury.

Diagnosis and treatment of ischemic colitis

Ischemic colitis (IC) is a common reason of acute lower gastrointestinal bleeding, and it is frequently seen in elderly people. In recent years, both the incidence and prevalence of IC have been rising. Most episodes of IC are transient and self-limited and only a minority of cases are severe. IC often has missed and delayed diagnosis. This review mainly focuses on the progress in the understanding of the diagnosis and therapy of IC.

Update on Colon Ischemia: Recent Insights and Advances

Colon ischemia (CI) is the most common manifestation of ischemic injury to the gastrointestinal (GI) tract. This usually self-limited disease is being diagnosed more frequently, and the list of known causes is increasing. Local hypoperfusion and reperfusion injury are both thought to contribute to the disease process, which manifests with a wide spectrum of injury including reversible colopathy (subepithelial hemorrhage and edema), transient colitis, chronic colitis, stricture, gangrene, and fulminant universal colitis. The distribution is usually segmental with left-sided disease (e.g., inferior mesenteric artery distribution) being more frequently observed than right-sided involvement (e.g., superior mesenteric artery distribution). Any portion of the colon can be affected, but the anatomic distribution of CI recently has been shown to be associated with outcome. Patients with isolated-right colon ischemia (IRCI) have a different presentation and worse outcomes than other distributions of disease. Although somewhat variable depending on disease location, CI presents with cramping abdominal pains over the segment of colon involved followed by a short course of bloody diarrhea. Diagnosis is usually made clinically and is supported with serologic, radiologic, and colonoscopic findings. Colonoscopy is the most accurate diagnostic study. Most patients respond to conservative supportive therapy although some with more severe disease require antimicrobials and/or surgical intervention.

Infectious causes of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency among premature infants. Although a large body of research has focused on understanding its pathogenesis, the exact mechanism has not been elucidated. Of particular interest is the potential causative role of infectious culprits in the development of NEC. A variety of reports describe bacterial, viral, and fungal infections occurring in association with NEC; however, no single organism has emerged as being definitively involved in NEC pathogenesis. In this review, the authors summarize the literature on infectious causes of NEC.

Changes of intestinal tight junctions in rat ileums after partial hepatectomy

BACKGROUND

Increased intestinal permeability and bacterial translocation have been observed after partial hepatectomy (PH).

METHODS

Rats (n = 40) were randomly divided into four groups: control; PH 1d, PH 3d and PH 5d. PH animals underwent two-thirds partial hepatectomy before sacrifice at 1, 3, or 5 days thereafter. The intestinal tight junction (TJ) morphology was observed by transmission electron microscopy. Distribution of TJ protein occludin in lipid raft microdomains was examined using Western blot analysis.

RESULTS

Intestinal TJ structures revealed significant changes at 1 day after PH that had partly recovered by 5 days. During this period, occludin protein decreased significantly in lipid raft microdomains, increasing partially by 5 days.

CONCLUSION

PH induced disruption of TJ structures in rat ilea, which was associated with redistribution of occludin protein in lipid raft microdomains.

Mutation, selection, and functional repair in formyl peptide receptor genes: a view on the selection processes occurring in this gene subfamily

Formyl peptides (FPs) released by some bacteria are powerful chemoattractants and activators of granulocytes, monocytes, and macrophages, acting through the members of a subfamily of specific seven-transmembrane G-protein-coupled formyl peptide receptors (FPRs), which are expressed only in mammals. Upon stimulation, granulocytes chemotactically move towards sites of maximal FP concentration, and release different bactericidal lytic enzymes and reactive oxygen species (ROI). In some instances, such as ischemia/reperfusion, the proinflammatory mediators released by the injured tissues and the intestinal bacteria and endotoxins, which may permeate across the damaged mucosal barrier, prime the inflowing granulocytes for an enhanced ROI production, resulting in severe damage to the host tissues. In this investigation 16 representative FPR and FPR-like mRNAs were selected to study the pattern of mutation/conservation of the individual nucleotides (nt) in the coding sequences. Mutations occur in 56.7%, 46.4%, and 87.5 % of cases in the first, second, and third nt, respectively, of the coding triplets. A probabilistic analysis demonstrated a significant nonrandom linkage between mutations in the first and second nt. Furthermore, the triplets that are variously double-mutated in the first two nt code, on average, for more hydrophobic amino acids (AA) in the transmembrane segments and more hydrophilic AA in the external and intracytoplasmic segments, thus preserving the general structure of the receptor. The authors hypothesize that when in one of the first two nt a mutation leading to a nonfunctioning protein product occurred, the mutated gene was eventually eliminated; however, a second mutation occurring in the other previously unmutated nt may have led to a protein product that is compatible with functional activity, although mutated in one (noncritical) AA. Such double mutations effecting a "functional repair" have thus survived and are retained among the extant sequences. Moreover, the combined mutation of all three nt in coding triplets occurs with a significantly higher than random frequency and this finding may be interpreted in a similar way.

Low mortality in necrotizing enterocolitis associated with coagulase-negative Staphylococcus infection

The aim of this study was to correlate the clinical course of necrotizing enterocolitis (NEC) with infection by coagulase-negative Staphylococcus at the onset of the illness. Records of all newborn infants developing NEC between January 1998 and December 2001 were reviewed. NEC was classified according to the criteria of Bell et al. Numeric variables were described by standard statistical methods. Comparisons between subgroups were performed by parametric statistical tests. Forty-four patients developed NEC stage II (n = 25) or III (n = 19). The incidence was 0.024% of live births in the hospital, and the mortality rate was 9%. The main risk factor was prematurity (84%). Only one-fourth of the patients had gastric residuals. A platelet count of <100,000 cells/mm3 occurred only in grade III NEC. Blood cultures were positive in 34% of the patients. The predominant organism (73%) was coagulase-negative Staphylococcus (CoNS). Neither Clostridium nor Bacteroides species were isolated. Stage II patients were maintained nothing per os (NPO) for 9 +/- 3 days and received antibiotics for 10 +/- 3 days. All of the stage III patients required an operation. In one-third of them, primary peritoneal drainage was initially performed but all required further operative procedures. We report a low incidence and mortality rate of necrotizing enterocolitis. Thrombocytopenia is confirmed as a marker of severity. Positive blood cultures for CoNS may explain, at least in part, the low mortality reported.

Maternal factors in extremely low birth weight infants who develop spontaneous intestinal perforation

BACKGROUND

Spontaneous intestinal perforation of the extremely low birth weight infant (< or = 1000 g) is associated with a high incidence of Candida and coagulase-negative Staphylococcus sepsis. Little is known about prenatal risk factors, and histopathologic examination of placentas in infants with spontaneous intestinal perforation has not been reported.

OBJECTIVES

Our objective was to investigate maternal factors and specific placental findings in a sample of infants with spontaneous intestinal perforation. We compared the maternal factors and clinical outcomes to a matched control group.

PATIENTS AND METHODS

This single-center, retrospective cohort study was conducted between January 2001 and December 2005. The records of extremely low birth weight infants with spontaneous intestinal perforation were reviewed (n = 16). Study infants were matched to 2 infants in the control group; any twin of a study patient was also included as a control subject (n = 35). Histopathologic examination of placentas included standard hematoxylin and eosin and methenamine silver stains.

RESULTS

Infants with spontaneous intestinal perforation were more likely than control subjects to have severe placental chorioamnionitis with fetal vascular response (40% vs 12%); 2 placentas also tested positive for yeast versus none in the control subjects. Mothers of infants with spontaneous intestinal perforation were more likely than control subjects to have received antibiotics before or at delivery (93% vs 57%). Fifty percent of the infants had Candida, and 31% in the spontaneous intestinal perforation group had coagulase-negative Staphylococcus sepsis versus 6% in the control subjects. Finally, infants with spontaneous intestinal perforation had delayed enteral feeding (64 +/- 30 vs 31 +/- 10 days) and prolonged hospitalization (155 +/- 48 vs 108 +/- 36 days).

CONCLUSIONS

Spontaneous intestinal perforation in the extremely low birth weight infant is a neonatal disease related to placental inflammation. We alert practitioners to the importance of placental findings, because they may be positive for yeast.

Surgical manipulation of the large intestine increases bacterial translocation in patients undergoing elective colorectal surgery

OBJECTIVE

Several animal studies have suggested that surgical manipulation of the intestine alters the barrier function and promotes bacterial translocation (BT). Whether this occurs in humans has never been investigated. The aim of this study was to determine the effect of surgical manipulation of the intestine on the prevalence of BT in patients undergoing elective colorectal surgery.

METHOD

This was a prospective observational study of 50 consecutive elective surgical patients in whom a sample of mesenteric lymph node (MLN) was harvested after mobilization of the colon, prior to ligation of the vascular pedicle. These results were compared with 472 historical controls, who had a sample of MLN taken before the mobilization of colon during laparotomy. A positive culture of MLN confirmed BT.

RESULTS

BT was identified in 39/49 (79.6%) patients in the study group compared with 54/472 (11.4%) patients in the control group. This difference was statistically significant (P < 0.001, chi(2) test).

CONCLUSION

Surgical manipulation of the bowel does increase the prevalence of BT and therefore is associated with changes in gut barrier function in elective surgical patients.

Dietary restriction compromises resistance to gut ischemia-reperfusion, despite reduction in circulating leukocyte activation

BACKGROUND

Gut ischemia-reperfusion (gut I/R) accompanying severe surgical insults leads to neutrophil-mediated injury and is regarded as a triggering event in early multiple-organ failure. Our previous study demonstrated dietary restriction to down-regulate leukocyte activation. Therefore, we hypothesized dietary restriction might be beneficial in terms of surviving I/R. We also evaluated leukocyte activation and the level of organ glutathione, an antioxidative substance.

METHODS

Institute of Cancer Research mice received chow, 170 (ad libitum), 119 (MR: mild restriction) or 68 (SR: severe restriction) g/kg per day for 7 days. Exp. 1: The mice (n = 59) underwent 15 or 45 minutes of gut ischemia and survival was observed. Exp. 2: The mice (n = 73) were killed before or 60 or 120 minutes after 15-minute ischemia. Reactive oxygen intermediate (ROI) production by circulating myeloid cells and CD11b expression was determined. Some mice were assessed for nuclear factor kappa B (NFkappaB) activation. Glutathione levels were measured in some of the small intestine and liver samples from each group.

RESULTS

Dietary restriction decreased survival. Circulating myeloid cell priming and activation, in terms of ROI production and CD11b expression, were enhanced in the ad libitum group but not in the restricted groups. NFkappaB was activated only in the ad libitum group. Gut and hepatic glutathione levels were lower in the SR than in the ad libitum group. Dietary restriction caused histologic damages in gut, liver, and lung 120 minutes after reperfusion.

CONCLUSIONS

Dietary restriction blunts leukocyte priming and activation after gut ischemic insult but worsens the outcome by, at least in part, decreasing antioxidative activities. Clinically, nutrition replenishment may be required to improve the outcome of gut hypoperfusion.