Patterns of Antimicrobial Resistance in the Causative Organisms of Spontaneous Bacterial Peritonitis: A Single Centre, Six-Year Experience of 1981 Samples
Patterns of Antimicrobial Resistance in the Causative Organisms of Spontaneous Bacterial Peritonitis: A Single Centre, Six-Year Experience of 1981 Samples
Sara Sheikhbahaei,1,2 Alireza Abdollahi,1 Nima Hafezi-Nejad,1,2 and Elham Zare1
1Department of Pathology, Imam Hospital Complex, Tehran University of Medical Sciences (TUMS), P.O. Box 14197-33141, Tehran, Iran
2Students’ Scientific Research Center (SSRC), Tehran University of Medical Sciences (TUMS), P.O. Box 14155-6537, Tehran, Iran
Received 14 December 2013; Revised 17 February 2014; Accepted 17 February 2014; Published 20 March 2014
Academic Editor: Matthias Bahr
Copyright © 2014 Sara Sheikhbahaei et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Background/Aims. Spontaneous bacterial peritonitis (SBP) is one of the leading causes of morbidity and mortality in patients with cirrhosis. This study aims to determine the microbial agents of SBP and the pattern of antibiotic resistance, in a large number of ascitic samples. Methodology. In a cross-sectional, single center, hospital based study, 1981 consecutive ascitic fluid samples were recruited from 2005 to 2011. Samples were dichotomized into three-year periods, in order to assess the trend of resistance to the first-line empirical antibiotics. Results. SBP was found in 482 (24.33%) of samples, of which 314 (65.15%) were culture positive. The most prevalent isolated pathogen was E. coli (33.8%), followed by staphylococcus aureus (8.9%) and Enterococcus (8.6%). No significant changes in the proportion of gram-negative/gram-positive infections occurred during this period. A percentage of resistant strains to cefotaxime (62.5%, 85.7%), ceftazidim (73%, 82.1%), ciprofloxacin (30, 59.8%), ofloxacin (36.8%, 50%), and oxacilin (35%, 51.6%) were significantly increased. E. coli was most sensitive to imipenem, piperacillin-tazobactam, amikacin, ceftizoxime, and gentamicin. Conclusions. The microbial aetiology of SBP remains relatively constant. However, the resistance rate especially to the first-line recommended antibiotics was significantly increased. This pattern must be watched closely and taken into account in empirical antibiotic treatment.
1. Introduction
Spontaneous bacterial peritonitis (SBP) is one of the leading causes of morbidity and mortality in patients with cirrhosis [1–3]. Unselected hospitalized cirrhotic patients with ascites were estimated to have 10%–30% risk of developing SBP [2, 3]. Early diagnosis and a prompt antibiotic therapy have considerably decreased the mortality rate associated with an episode of SBP from 80% to approximately 20–30% in the last decade [1, 2, 4–6].
SBP is defined as a monomicrobial infection of the ascitic fluid, which is not accompanied by a definite evidence of a surgically treatable origin [1, 3, 4]. The infection occurs following a translocation or haematogenous dissemination of the intestinal flora. Intestinal bacterial overgrowth can also exacerbate the condition [1, 3]. Studies have indicated that gram-negative Enterobacteriaceae such as Escherichia coli (E. coli) was the most common isolated organisms in SBP [1, 3, 7].
Diagnosis of SBP is established by an elevated ascitic fluid polymorphonuclear leukocyte (PMNL) count (≥250 cells/mm3) [1, 3, 4]. Some studies suggest that the type and the etiology of SBP have been changing in the recent years. Involvement with gram-positive bacteria and increased frequency of multiple antibiotic resistant bacteria are evidences that support this viewpoint [6, 8, 9].
Based on EASL guidelines, third-generation cephalosporins (including cefotaxime and ceftriaxone) are recommended as the first-line therapy [1–4]. However, knowledge about the local epidemiological pattern of antibiotic resistance would be necessary for an effective treatment [2]. According to the pattern of antibiotic consumption, great differences exist in antibiotic sensitivity and resistance among various countries. Meanwhile, information regarding the spectrum of the involved bacteria and the pattern of antibiotic resistance in developing countries is scarce. The present study aims to determine the current causative agents of SBP and the pattern of antibiotic resistance, in a large number of ascitic samples. The antibiotic susceptibility patterns are delineated by in vitro methods. We further assess the trends of resistance to the first-line empirical antibiotics within a six-year period. The result of this study could be implicated in future management and treatment of patients with SBP in similar settings.
2. Methodology2.1. Samples
This cross-sectional hospital based study was conducted in Imam Hospital Complex affiliated to the Tehran University of Medical Sciences, Iran. All ascitic fluid samples, referred to the pathology division of the hospital from April 2005 t (...truncated)