Abstract
Objective: To investigates Spontaneous Bacterial Peritonitis (SBP) bacteria, their antibiotic sensitivity and resistance.
Methodology: From January 2013 to October 2019, 99 adult patients of both gender with cirrhosis and ascites were admitted to Baghdad Medical city complex with decompensated cirrhosis as encephalopathy, new gastrointestinal bleeding, increasing ascites, abdominal pain, and/or fever and were labelled SBP after ascetic fluid analysis. Causative agent, its antibiotic sensitivity and resistance were recorded.
Results: Mean age of patients was 52±11 years, 72.7% were men and 27.3% women, 53.5% are middle-aged adults, and 31.3% are geriatrics (over 60). E-coli (36.36%) was the most common bacterium recovered, followed by enterobacter (15.15%) and staphylococcus (13.13%). There was a correlation between age and bacteria. E-coli infected 46.7% of young adults, 32.1% of middle-aged, and 38.7% of geriatrics. S. aureus infected 26.7% of young people and Enterobacter 20.8% of middle-aged individuals. Ampicillin and cefepime were very effective to Stenotrophomonas maltophilia and Streptococcus pneumoniae. Amikacin and ciprofloxacin had good Pseudomonas and Proteus sensitivity. Cefotaxime, ceftazidime, ceftriaxone, cotrimoxazole, imipenem, meropenem, piperacillin-tazobactam, and vancomycin were effective against their pathogens.
Conclusion: E-coli and Enterobacter caused SBP, which affected middle-aged men. These findings highlight the need of choosing antibiotics based on pathogen susceptibility to optimise SBP therapy.

Key words: Spontaneous bacterial peritonitis, microorganisms, antibiotic, sensitivity, resistant pattern.