Spontaneous bacterial peritonitis: clinico-epidemiological and microbiological study

ABSTRACT

Spontaneous bacterial peritonitis [SBP] is a frequent severe and potentially life-threatening complication of cirrhotic patients with ascites. The clinical presentation of SBP depends on the stage at which the infection is diagnosed. In early stages, most patients are asymptomatic or present with insidious, non specific symptoms. As the disease progresses, patients show signs and symptoms of peritoneal infection. To determine the prevalent pathogens responsible for SBP in our locality and their sensitivity pattern, to test the efficiency of different culture techniques in microbial isolation, and to study the diagnostic predictors of such cases. Two hundred fifteen adults with cirrhotic ascites consecutively admitted to Tropical Medicine Unit Mansoura University Hospital were screened for SBP. One hundred eight SBP episodes from 92 adult patients were compared to 88 cirrhotic ascites patients cross-matched with age and sex without SBP. Diagnosis of cirrhosis was based on clinical biochemical radiological and/or histo-pathological data. Ascitic fluid was subjected to cytological biochemical examination and culture on both conventional and blood culture bottles at the bedside for bacterial identification and antimicrobial susceptibility testing. Diagnosis of SBP and its variants were made depending on ascitic fluid poly-morphnuclear count >/= 250 cell/ mm[3] and/or monomicrobial growth in ascitic fluid culture without evidence of an infra-abdominal surgically treatable source of infection, and no recent use of antibiotics. A total of 432 diagnostic paracentesis were performed in 215 cirrhotic patients with ascites. The prevalence of SBP was 25.02%. History of previous episode of SBP or history of paracentesis were significantly more frequent in SBP patients [P=0.000 and P=0.001] respectively also, Abdominal wall edema and redness [cellulitis], presence of ascetic fluid with numerous fine internal hyper-echoic particulates by ultrasonography and the aspiration of slightly turbid ascites were significantly more frequent in SBP patients [P= 0.01, P=0.031 and P=0.035] respectively. Ascitic fluid protein levels and serum albumin levels were significantly lower and serum creatinine levels were significantly higher in SBP patients. [P=0.009, P=0.03, and P= 0.003] respectively. Applying the model of logistic regression analysis between SBP and Non SBP clinical and laboratory data revealed that; previous SBP episode, low ascitic fluid protein levels, high serum creatinine and low serum albumin levels were significant predictors of SBP [P-0.000]. Fourty-nine [45.37%] episodes of SBP were detected by the conventional culture compared to 79 [73.15%] by modified technique with a significant P value <0.001. Gram-negative bacteria were the cause of SBP in 46 [58.23%] culture positive episodes while Gram-positive bacteria were the isolated organisms in 33 cases [41.77%]. Escherichia coli and Staphylococcus aureus were the most commonly detected organisms in 40 [50.63%] and 26 [32.91%] cases respectively. In this study, 31.65% of cultures were highly sensitive to Levofloxacin, 29.11% were sensitive to Cefotaxime, 20.25% were sensitive to Amoxicillin-Clavulanic acid, 18.99% were sensitive to Meropenem, 17.72% were sensitive to Ciprofloxacin and 15.19% were sensitive to Ceftazidime. On the other hand, antibiotic resistant rates to Ciprofloxacin were 25.32%, 24.05% to Ceftazidime and 21.52% to Cefotaxime. Previous SBP episode, low ascetic fluid protein levels, high serum creatinine, and low serum albumin levels, all had a significant prediction of SBP. Beside cytological and biochemical examination, culture of ascitic fluid in blood culture bottles at bedside increases the sensitivity of SBP detection and must be a routine in every hospitalized patient with cirrhotic ascites. Gram-negative organisms still, the prevalent microorganisms causing SBP but there is a significant recent increase in Gram-posittue pathogen with emergence of maltidrug resistance especially for Ciprofloxacin, Ceftazidime and Cefotaxime. These recent changes may have an impact on guidelines for management and treatment of SBP in oar locality