Microbial spectrum and drug resistance of pathogens cultured from gallbladder bile specimens of patients with cholelithiasis:A singlecenter retrospective study

BACKGROUND Bacterial infection is an important cause of cholelithiasis or gallstones and interferes with its treatment.There is no consensus on bile microbial culture profiles in previous studies,and identified microbial spectrum and drug resistance is helpful for targeted preventive and therapeutic drugs in the perioperative period.AIM To analyze the bile microbial spectrum of patients with cholelithiasis and the drug susceptibility patterns in order to establish an empirical antibiotic treatment for cholelithiasis-associated infection.METHODS A retrospective single-center study was conducted on patients diagnosed with cholelithiasis between May 2013 and December 2018.RESULTS This study included 185 patients,of whom 163(88.1%)were diagnosed with gallstones and 22(11.9%)were diagnosed with gallstones and common bile duct stones(CBDSs).Bile culture in 38 cases(20.5%)was positive.The presence of CBDSs(OR=5.4,95%CI:1.3-21.9,P=0.03)and longer operation time(>80 min)(OR=4.3,95%CI:1.4-13.1,P=0.01)were identified as independent risk factors for positive bile culture.Gram-negative bacteria were detected in 28 positive bile specimens,and Escherichia coli(E.coli)(19/28)and Klebsiella pneumoniae(5/28)were the most frequently identified species.Gram-positive bacteria were present in 10 specimens.The resistance rate to cephalosporin in E.coli was above 42%and varied across generations.All the isolated E.coli strains were sensitive to carbapenems,with the exception of one imipenem-resistant strain.K.pneumoniae showed a similar resistance spectrum to E.coli.Enterococcus spp.was largely sensitive to glycopeptides and penicillin,except for a few strains of E.faecium.CONCLUSION The presence of common bile duct stones and longer operation time were identified as independent risk factors for positive bile culture in patients with cholelithiasis.The most commonly detected bacterium was E.coli.The combination ofβ-lactam antibiotics andβ-lactamase inhibitors prescribed perioperatively appears to be effective against bile pathogens and is recommended.Additionally,regular monitoring of emerging resistance patterns is required in the future.

Microbiology of gallbladder bile in uncomplicated symptomatic cholelithiasis

BACKGROUND:Few studies have assessed microflora and their antibiotic sensitivity in normal bile and lithogenic bile with different types of gallstones. METHODS:We performed a case control study of 70 bile samples(35 cholesterol and 35 pigment stones from 51 females and 19 males,aged 21-72 years with a median age of 37 years)from patients who underwent laparoscopic cholecystectomy for uncomplicated cholelithiasis,and 20 controls(14 females and 6 males,aged 33-70 years with a median age of 38 years)who underwent laparotomy and had no gallbladder stone shown by ultrasound scan.The bile samples were aerobically cultured to assess microflora and their antibiotic susceptibility.The procedures were undertaken under sterile conditions. RESULTS:Thirty-eight(54%)of the 70 patients with gallstones had bacterial isolates.Nine isolates(26%)were from cholesterol stone-containing bile and 29 isolates (82%)from pigment stone-containing bile(P=0.01,t test). Twenty-eight of these 38(74%)bile samples were shown positive only after enrichment in brain heart infusion medium(BHI)(P=0.02,t test).The overall bacterial isolates from bile samples revealed E.coli predominantly,followed by P.aeruginosa,Enterococcus spp.,Klebsiella spp.and S. epidermidis.There were no bacterial isolates in the bile of controls after either direct inoculation or enrichment in BHI.CONCLUSIONS:Bacterial isolates were found in pigment stone-containing bile.Non-lithogenic bile revealed no bacteria,showing an association between gallstone formation and the presence of bacteria in bile.Antibiotic sensitivity patterns of isolated organisms were similar irrespective of the type of stone.