Review article: spontaneous bacterial peritonitis--bacteriology, diagnosis, treatment, risk factors and prevention

BACKGROUND

Spontaneous bacterial peritonitis (SBP) is a severe and often fatal infection in patients with cirrhosis and ascites.

AIM

To review the known and changing bacteriology, risk factors, ascitic fluid interpretation, steps in performing paracentesis, treatment, prophylaxis and evolving perspectives related to SBP.

METHODS

Information was obtained from reviewing medical literature accessible on PubMed Central. The search term 'spontaneous bacterial peritonitis' was cross-referenced with 'bacteria', 'risk factors', 'ascites', 'paracentesis', 'ascitic fluid analysis', 'diagnosis', 'treatment', 'antibiotics', 'prophylaxis', 'liver transplantation' and 'nutrition'.

RESULTS

Gram-positive cocci (GPC) such as Staphylococcus, Enterococcus as well as multi-resistant bacteria have become common pathogens and have changed the conventional approach to treatment of SBP. Health care-associated and nosocomial SBP infections should prompt greater vigilance and consideration for alternative antibiotic coverage. Acid suppressive and beta-adrenergic antagonist therapies are strongly associated with SBP in at-risk individuals.

CONCLUSIONS

Third-generation, broad-spectrum cephalosporins remain a good initial choice for SBP treatment. Levofloxacin is an acceptable alternative for patients not receiving long-term flouroquinolone prophylaxis or for those with a penicillin allergy. For uncomplicated SBP, early oral switch therapy is reasonable. Alternative antibiotics such as pipercillin-tazobactam should be considered for patients with nosocomial SBP or for patients who fail to improve on traditional antibiotic regimens. Selective albumin supplementation remains an important adjunct in SBP treatment. Withholding acid suppressive medication deserves strong consideration, and discontinuing beta-adrenergic antagonist therapy in patients with end-stage liver disease and resistant ascites is standard care. Liver transplant evaluation should be undertaken for patients who develop SBP barring contraindications.

Monotypic angiomyolipoma of the nasal cavity: a heretofore undescribed occurrence

A monotypic angiomyolipoma of the nasal cavity in a 34-year-old woman is described. Tumor cells were spindled or epithelioid and contained glycogen and diastase-resistant PAS-positive granules. There were few mitoses, and necrosis was absent, indicating a benign tumor. The stroma was markedly vascular, and a few adipocytes were seen in one area. Cells were positive for melanocyte and muscle markers. Electron microscopy revealed abundant dense granules. Although melanin was absent histochemically, it was present using a chemical assay, and the granules may, therefore, be atypical melanosomes. Fine actin filaments, attachment plaques and lamina were present. Initial assessment of the lesion indicated malignant melanoma, but the immunostaining and histologic features indicated monotypic angiomyolipoma. To the best of our knowledge, this is the first such case in the nasal cavity.

Percutaneous transhepatic biliary stenting

OBJECTIVE

Bilary stenting with endoprosthesis is a palliative procedure to relieve malignant biliary obstruction. Percutaneous transhepatic technique has been employed whenever endoscopic technique was not possible or had failed.

SETTING

Angiography/intervention suite, department of radiology, Aga Khan University hospital, Karachi.

METHODS

We present retrospective analysis of 17 patients with malignant jaundice who were treated with percutaneous techniques after the endoscopic route had failed.

RESULTS

The success rate was 94% with placement of single plastic stent in 14 patients, double stents in 3 patients and self-expandable stent in one patient. The overall complication rate was 41% including sepsis, liver abscess, biloma formation, biliary leakage and stent occlusion. There was one procedure related death due to severe sepsis.

CONCLUSION

Percutaneous transhepatic biliary stenting is an alternative procedure to relieve malignant biliary obstruction with high complication rate and should be reserved for selected patients in whom endoscopic route has failed.

Effect of long-term trimethoprim-sulfamethoxazole prophylaxis on ascites formation, bacterial translocation, spontaneous bacterial peritonitis, and survival in cirrhotic rats

Selective intestinal decontamination with norfloxacin is useful in preventing spontaneous bacterial peritonitis in cirrhotic patients and also in cirrhotic rats. The emergence of norfloxacin-resistant infections in these patients warrants a search for alternative therapies. The aim of this study was to evaluate the effect of long-term trimethoprim-sulfamethoxazole administration on carbon tetrachloride (CCl4) -induced cirrhosis in rats with specific attention to intestinal flora, bacterial translocation, spontaneous bacterial peritonitis (SBP), and survival. Male Sprague-Dawley rats received CCl4 administered weekly by gavage. After eight weeks of CCl4 administration rats were randomly allocated into two groups. Group I received daily overnight trimethoprim-sulfamethoxazole diluted in phenobarbital water during follow-up and group II did not. The rats were killed when gravely ill, and a laparotomy was performed to culture samples of cecal stool, mesenteric lymph nodes, and portal and inferior vena caval blood. There was a trend toward a reduction in the incidence of bacterial translocation (8/17 vs 11/14, respectively) and SBP (5/17 vs 7/14, respectively) in treated rats that were killed just before death compared to untreated rats. A decrease in the incidence of bacterial translocation caused by gram-negative bacilli was observed in group I (17.6% vs 78.6%, P < 0.01). The development of ascites was delayed in group I (P < 0.05) and survival was prolonged in group I (P < 0.05), despite a higher CCl4 dose in this group (P < 0.05). In conclusion, long-term prophylactic trimethoprim-sulfamethoxazole administration in CCl4-induced cirrhosis in rats delayed the development of ascites, prolonged survival, and reduced the incidence of gram-negative bacterial translocation but not of SBP, without increasing gram-positive episodes. These data suggest that trimethoprim-sulfamethoxazole might be a good alternative to norfloxacin for preventing gram-negative bacterial translocation.

Non-visualization of lung markings below hemidiaphragm in subtle subpulmonic effusion: an old sign resuscitated

To assess the lack of visibility of vascular markings under the hemidiaphragm on a frontal chest radiograph as a sign of pleural effusion, fifteen patients were collected showing this sign. Pleural effusion was diagnosed by ultrasound, comparison with previous or subsequent chest x-ray or computed tomography. Patients in the study group exhibited this sign in the absence of the classical signs of pleural effusion. In the control group, lack of visibility of blood vessels was observed in only 4.2% cases. Non-visualization of vascular markings below the hemidiaphragm should alert the interpreter to the possible presence of pleural effusion and a lateral or decubitus view or ultrasound examination may be carried out to rule out effusion.

Intestinal bacterial overgrowth and bacterial translocation in cirrhotic rats with ascites

BACKGROUND/AIMS

Translocation of indigenous bacteria from the gut lumen of cirrhotic animals to mesenteric lymph nodes appears to be an important step in the pathogenesis of spontaneous bacterial peritonitis. However, the sequence of events leading to translocation remains unclear. One of the most predictable risk factors for translocation is overgrowth of gut bacterial flora. The present study was designed to compare the intestinal aerobic bacterial flora of cecal stools at the time of sacrifice between cirrhotic and normal rats and to evaluate the role of intestinal aerobic bacterial overgrowth in bacterial translocation in cirrhotic rats.

METHODS

Thirty-five male Sprague-Dawley rats with carbon tetrachloride-induced cirrhosis and ascites and 10 normal rats were included in this study. Cirrhotic rats were sacrificed when ill and samples of ascitic fluid, mesenteric lymph nodes and cecal stool were taken for detecting quantitatively aerobic bacteria.

RESULTS

Total intestinal aerobic bacterial count in cecal stool at the time of sacrifice was significantly increased in cirrhotic rats with bacterial translocation with or without spontaneous bacterial peritonitis compared to cirrhotic rats without bacterial translocation (p<0.001 and p<0.001, respectively) and to normal rats (p<0.001 and p<0.001, respectively). Of the 42 species of bacteria translocating to the mesenteric lymph nodes, 41 (97.6%) were found in supranormal numbers in the stool at the time of sacrifice.

CONCLUSIONS

Carbon tetrachloride-induced cirrhotic rats with bacterial translocation have increased total intestinal aerobic bacteria count, and intestinal bacterial overgrowth appears to play an important role in bacterial translocation in this experimental model of cirrhosis in rats.

AIDS-related non-Hodgkin's lymphoma of the pancreas

Non-Hodgkin's lymphoma is a common complication in patients with human immunodeficiency virus infection that most frequently affects the gastrointestinal tract. We describe the first case report of non-Hodgkin's lymphoma primarily involving the pancreas in a 27-yr-old white man who presented with epigastric pain, weight loss, and jaundice (and was later found to be HIV seropositive). Endoscopic ultrasound and CT scan of the abdomen showed a large mass arising from the body and head of the pancreas obstructing the common bile duct. An attempted ERCP was unsuccessful due to extrinsic compression and distortion of the second part of the duodenum. A percutaneous CT-directed true-cut needle biopsy of the pancreas revealed a small noncleaved B-cell lymphoma. The patient was started on combination chemotherapy. His pancreatic mass, epigastric symptoms, and jaundice resolved completely. This case report illustrates an otherwise rare presentation of isolated pancreatic involvement of non-Hodgkin's lymphoma in a patient with acquired immunodeficiency syndrome. An approach to its diagnosis and management is summarized.

Computed tomography appearance of malignant schwannoma of the liver

Malignant schwannoma of the liver without associated neurofibromatosis is rare. The authors present one such case in a 35-year-old woman. Computed tomography demonstrated large liver masses with contiguous involvement of adjacent stomach tissue, consistent with local invasion.

Microbial reduction of the side-chain carbonyl of daunorubicin and N-acetyldaunorubicin

Microorganisms reduced the side-chain carbonyl of daunorubicin to yield 13-dihydrodaunorubicin (daunorubicinol; daunomycinol). This microbial transformation occurred under aerobic conditions in agitated baffled shake flasks incubated at 37 degrees C. The microorganisms were first grown in a medium which supported dense growth. Daunorubicin-HCl was then added. Following a period of incubation, broths were adjusted to pH 10.0 and extracted with chloroform. Daunorubicinol was recovered and purified from the chloroform extracts by preparative TLC. Identity of the daunorubicinol was established by TLC and spectroscopy (UV-vis, IR, NMR, MS, CD and ORD). N-Acetyldaunorubicin was likewise reduced microbially to N-acetyldaunorubicinol. N-Acetyldaunorubicinol appears to be a new compound which is yet to be tested for antitumor activity.