Microbial Profile and Antibiotic Susceptibility of Organisms in Bile Cultures from Patients Undergoing Endoscopic Retrograde Cholangiography: A Cross-Sectional Study from a Tertiary-Care Center in Nepal

Abstract

Background

Acute cholangitis, a potentially life-threatening biliary infection, frequently arises from biliary obstruction. Prompt diagnosis and appropriate antimicrobial therapy are critical to preventing sepsis and reducing mortality. Empirical antibiotic selection requires an understanding of local microbial profiles and resistance patterns.

Objectives

This study aims to describe the microbial profile and antibiotic resistance patterns in bile cultures obtained from patients undergoing endoscopic retrograde cholangiography (ERC) at a tertiary-care teaching hospital in Kathmandu, Nepal, and assess if there is a difference in prevalence rates between these groups.

Methods

This cross-sectional study was conducted at a tertiary-care teaching hospital in Nepal between November 2023 and April 2024. A total of 88 patients (44 with acute cholangitis and 44 without) undergoing ERC were included. Bile samples were aseptically collected, cultured, and analyzed for microbial identification and antibiotic susceptibility. Statistical analysis was performed with a two-tailed two-sample proportion z-test to compare bile culture positivity and microbial patterns between groups.

Results

Of the 88 patients, 74 (84%) had positive bile cultures, with a significantly higher prevalence in the cholangitis group (93%) compared with those without cholangitis (75%, p = 0.041). Gram-negative organisms predominated, with Escherichia coli (38%), Citrobacter (30%), and Klebsiella (19%) being the most common. Pseudomonas species were isolated exclusively in the cholangitis group. Antibiotic resistance rates were high, including multidrug resistance among Pseudomonas and Enterobacter isolates.

Conclusion

This study highlights the high prevalence of gram-negative pathogens in ERC patients with cholangitis, emphasizing targeted empiric therapy and antimicrobial stewardship.

Keywords

acute cholangitis - endoscopic retrograde cholangiography - antibiotic resistance - Nepal

Introduction

Bile in the normal biliary tract is typically sterile.[1] Bacteria may enter the biliary system through several ways: through retrograde ascent from the duodenum, translocation from the portal vein, or during procedures such as stone removal or stent placement.[2] In normal bile flow, these bacteria usually remain clinically insignificant. However, bile duct obstruction can increase biliary pressure, creating an environment that favors bacterial proliferation in stagnant bile. This rise in intraductal pressure, coupled with the local inflammatory response, can compromise biliary epithelium integrity, allowing bacteria to enter the circulation and cause systemic infections, including acute cholangitis.[3]

Acute cholangitis can range in severity from mild to life-threatening, with a mortality rate as high as 10%. However, timely and appropriate treatment can reduce mortality to less than 5%.[4] Managing acute cholangitis involves prompt hemodynamic resuscitation, appropriate antimicrobial therapy, and definitive source control through biliary decompression.[5] Early empiric antibiotic administration is recommended when acute cholangitis is suspected or confirmed.[6]

Empirical antibiotic selection should consider antimicrobial activity against the most likely causative organisms, disease severity, patient comorbidities, recent antibiotic use, local resistance patterns, and biliary penetration, followed by narrowing of the antibiotic therapy based on culture results and susceptibility profiles when they become available.[7] The most common isolates, and their antimicrobial susceptibility patterns, vary across the settings and patient demographics.

The variations in the pathogens isolated, the regional differences in the patient demographics, and clinical characteristics, as well as changing patterns due to the increased use of biliary stents and prior antimicrobial exposure, particularly, a rise in infections caused by extended-spectrum β-lactamase-producing gram-negative bacteria in both community-acquired and hospital-acquired infections, highlight the crucial need for an understanding and local data on the common etiological agents and their susceptibility patterns for the timely initiation of appropriate empirical therapy.[8] [9]

This study aims to describe the microbial profile and antibiotic resistance patterns in bile cultures obtained from patients undergoing endoscopic retrograde cholangiography (ERC) at a tertiary-care teaching hospital in Kathmandu, Nepal, and to determine if there is a difference in prevalence rates between these groups.

Methods

Study Design and Setting

This cross-sectional study was conducted at the Department of Gastroenterology, Bir Hospital, National Academy of Medical Sciences, Kathmandu, Nepal, from November 2023 to April 2024. The study was designed, and the findings were reported in accordance with the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) guidelines ([Supplementary Material], available in online version only).

Study Participants

All the consecutive patients aged ≥ 18 years undergoing ERC at the Department of Gastroenterology in a tertiary-care teaching hospital in Kathmandu, Nepal, were screened. Patients in whom bile could not be aspirated, or the sample was inadequate for evaluation, those already on a percutaneous transhepatic biliary drainage (PTBD) catheter or other abdominal drainage tubes or concurrent non-biliary intra-abdominal infections, or who have received 2 or more days of intravenous antibiotics were excluded from the study.

Sample Size Calculation

Sample size was calculated using the “pwr” package in R (R core team, Vienna, Austria, 2023). With the critical value of the normal distribution at α/2 (Z_α/2) taken as 1.96, the critical value of the normal distribution at β (Z_β) taken at 0.84 for a power of 80%, the expected proportion of positive bile culture in the ERC patients with acute cholangitis (p1) taken as 67%, the expected proportion of positive bile culture in the ERC patients without acute cholangitis (p2) taken as 33%, a type I error of 5%, and a type II error of 20%, a sample size of 66 (33 each with cholangitis and no cholangitis) was obtained.[4] After accounting for a 25% non-response rate, the sample size obtained was 88 (44 each with cholangitis and no cholangitis).

Case Definitions

The diagnosis of acute cholangitis and its severity classification were made according to the Tokyo guidelines TG18/TG13. Acute cholangitis was suspected when at least one indicator of systemic inflammation (fever and/or shaking chills, or laboratory evidence of an inflammatory response) was present, along with either one indicator of cholestasis (jaundice or abnormal liver function tests) or one imaging finding (biliary dilatation or evidence of etiology like stricture, stone, or stent). A definitive diagnosis of acute cholangitis was made when at least one indicator from each of the following categories was present: systemic inflammation (fever and/or laboratory evidence of inflammation), cholestasis (jaundice or abnormal liver function tests), and imaging (biliary dilatation or an identifiable cause on imaging such as a stone or stricture).[5] The severity of acute cholangitis was graded as outlined in [Table 1]. Bacteriobilia was defined as the presence of microorganisms in the bile, documented by at least one positive bile culture.[5]

Table 1 Severity of acute cholangitis

Grade III (severe) acute cholangitis if at least one major organ or system
Organ/System	Dysfunction criteria
Cardiovascular	Hypotension requiring dopamine ≥5 mg/kg/min or any dose of norepinephrine
Neurological	Disturbances in consciousness
Respiratory	PaO2/FiO2 ratio < 300
Renal	Oliguria or serum creatinine > 2.0 mg/dL
Hepatic	PT/INR > 1.5
Hematological	Platelet count <100,000/mm3
Grade II (moderate) acute cholangitis if any two of the following
Criteria	Definition
Abnormal white blood cell (WBC) count	WBC > 12,000/mm3 or WBC < 4,000/mm3
High fever	Temperature ≥ 39 °C
Advanced age	≥ 75 years old
Hyperbilirubinemia	Total bilirubin ≥ 5 mg/dL
Hypoalbuminemia	Albumin < 70% of lower limit of normal value
Grade I (mild)
Patients who did not meet the criteria for Grade II (moderate) or Grade III (severe) acute cholangitis at the time of diagnosis

Data Collection

All the consecutive patients undergoing ERC at the Department of Gastroenterology were evaluated with a detailed history regarding the etiology of the disease and indication of the procedure. A thorough clinical examination was performed to assess hemodynamic stability, the severity of the disease, and the presence of other underlying comorbidities. Baseline blood and imaging studies were performed. All duodenoscopes used for ERC were manually precleaned. The external surface, port openings, and connector caps were cleaned with a soft-bristle toothbrush, sponge, and washcloth. While immersed in a bacteriostatic solution, the accessible channels were brushed, and the solution was flushed through the air–water and suction-accessory channels using a sterile syringe. A vacuum pump suctioned the solution through the suction-accessory channel. The duodenoscope was then rinsed with tap water, with water suctioned and flushed through the channels. After rinsing, it was immersed in 2.6% glutaraldehyde for 30 minutes and then rinsed with sterile water.

At ERC, bile specimens were collected before contrast injection using a sterile catheter (Ultratome XL Short Nose Sphincterotome from Boston Scientific, 200 cm catheter length with 5.5-Fr distal tip outer diameter) inserted into the common bile duct. Two to 8 mL of bile was aspirated into a sterile syringe and transferred to a sterile tube or syringe to the microbiology laboratory for cultivation, incubation, and microbial testing. Antimicrobial susceptibility testing was performed using the modified Kirby-Bauer disk diffusion method and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) M100 guidelines.[10] The susceptibility results for each isolate were classified as susceptible, intermediate, or resistant based on CLSI-defined breakpoints for each organism–antibiotic pair.

Statistical Analysis

Data were collected in the structured data collection sheet and entered into Microsoft Excel 365 (Microsoft Corporation, Redmond, Washington, United States). The analysis was done in R (R Core Team 2024, R Foundation for Statistical Computing, Vienna, Austria). Descriptive analyses were done with a mean (and standard deviation) or median (and interquartile range) and proportions as appropriate. The prevalence of positive (and negative) bile cultures was obtained as the proportion of patients with organisms isolated (and not isolated) from the bile samples among the patients whose bile samples were collected during ERC. To assess if the positive bile culture rate from ERC patients is different from that without acute cholangitis, a two-tailed two-sample proportion z-test was used. The p-value of <0.05 was considered significant.

Results

Of the 132 patients screened for eligibility, 88 patients (44 with acute cholangitis and 44 without acute cholangitis) undergoing ERC were studied. The median age of the study participants was 54.5 years (IQR: 41.75–68), and 52 (59%) of them were females ([Table 2]). Most of them had choledocholithiasis (n = 60, 68%) and no prior biliary procedure (n = 51, 58%).

Table 2 Characteristics of the study population

Characteristics	Frequency (n)	Percentage
Age in years
30 y or below	5	6%
31–50	32	36%
51–70	36	41%
>71	15	17%
Sex
Male	36	41%
Female	52	59%
Diagnosis
Choledocholithiasis	60	68%
Biliary stricture	6	7%
Malignancy
Cholangiocarcinoma	10	11%
Ampulla of Vater tumor	5	6%
Pancreatic cancer	4	5%
Gall bladder carcinoma	0	0%
Metastatic carcinoma	0	0%
Bile leakage
Chronic/Recurrent pancreatitis	1	1%
Obstructive jaundice of undetermined cause	0	0%
Portal biliopathy	1	1%
Others	1	1%
History of biliary procedure
No	51	58%
Biliary stent placement	24	27%
Cholecystectomy and biliary stent placement	7	8%
Cholecystectomy	6	7%
Biliary anastomosis	0	0%
Acute cholangitis
No cholangitis	44	50%
Mild cholangitis	23	26%
Moderate cholangitis	21	24%
Severe cholangitis	0	0%

[Table 3] compares the study participants with acute cholangitis with those without acute cholangitis. Patients with cholangitis were more likely to be male (55 vs. 27%) and had a higher prevalence of positive bile cultures (93 vs. 75%) compared with those without cholangitis. Choledocholithiasis was the most common diagnosis in both groups, though it was more frequent in the non-cholangitis group (80 vs. 57%). The history of biliary procedures was more common in patients without cholangitis (55 vs. 30%). Malignancies were more prevalent in patients with cholangitis (32 vs. 16%), particularly cholangiocarcinoma and pancreatic cancer.

Table 3 Characteristics of patients with and without cholangitis

Characteristics	Patients with cholangitis	Patients without cholangitis	Total
	n = 44 (%)	n = 44 (%)	n = 88 (%)
Age in years (median, IQR)	53.5 (43–62.25)	54.5 (41.75–69.25)	54.5 (41.75–68)
Sex
Male	24 (55%)	12 (27%)	36 (41%)
Female	20 (45%)	32 (73%)	52 (59%)
Diagnosis
Choledocholithiasis	25 (57%)	35 (80%)	60 (68%)
Biliary stricture	3 (7%)	3 (7%)	6 (7%)
Malignancy
Cholangiocarcinoma	8 (18%)	2 (5%)	10 (11%)
Ampulla of Vater tumor	2 (5%)	3 (7%)	5 (6%)
Pancreatic cancer	4 (9%)	–	4 (5%)
Gall bladder carcinoma	–	–	–
Metastatic carcinoma	–	–	–
Bile leakage	–	–	–
Chronic/Recurrent pancreatitis	–	1 (2%)	1 (1%)
Obstructive jaundice of undetermined cause	–	–	–
Portal biliopathy	1 (2%)	–	1 (1%)
Others	1 (2%)	–	1 (1%)
History of biliary procedure
Yes	13 (30%)	24 (55%)	37 (42%)
No	31 (70%)	20 (45%)	51 (58%)
Number of patients with positive culture results	41 (93%)	33 (75%)	74 (84%)

Out of the total 88 bile samples collected, 74 (84%) yielded positive bile cultures, while 14 (16%) showed no growth. Among the patients with acute cholangitis, 41 (93%) had positive bile cultures, compared with 33 (75%) in those without acute cholangitis. The prevalence of positive bile cultures was significantly higher in patients with acute cholangitis compared with those without; the results of the two-sample proportion z-test indicated a statistically significant difference between the two groups (χ ² = 4.16, df = 1, p = 0.041). The 95% confidence interval for the difference in proportions was 1.1 to 35.2%.

The microbial analysis revealed a predominance of gram-negative organisms, with Escherichia coli being the most isolated pathogen, accounting for 38% of positive cultures (28 out of 74). Other frequently identified organisms included Citrobacter (30%, 22 out of 74) and Klebsiella (19%, 14 out of 74). Gram-positive organisms such as Enterococcus faecalis were isolated in only one of the 74 positive cultures ([Table 4]).

Table 4 Bile culture results in patients with and without cholangitis

Characteristics	Patients with cholangitis	Patients without cholangitis	Total
	n = 44	n = 44	n = 88
Gram-negative organisms
E. coli	16	12	28
Citrobacter	13	9	22
Klebsiella	5	9	14
Pseudomonas	5	0	5
Morganella	1	1	2
Proteus	0	2	2
Enterobacter	1	0	1
Stenotrophomonas	0	0	0
Gram-positive organisms
Enterococcus	0	1	1
Staphylococcus	0	0	0
Streptococcus	0	0	0
Lactobacillus	0	0	0

E. coli and Citrobacter species showed the highest proportion of resistance to ampicillin–sulbactam. E. coli also demonstrated considerable resistance to Ciprofloxacin, while Klebsiella and Pseudomonas species exhibited resistance to multiple antibiotic classes, including third-generation cephalosporins and carbapenems. [Table 5] reports the percentage of isolates susceptible to each antibiotic. To facilitate the interpretation, color coding is used to represent levels of susceptibility: green for high susceptibility (when ≥90% of the isolates are susceptible to that antimicrobial), yellow for intermediate susceptibility (when 50–89% of the isolates are susceptible to that antimicrobial), and red for low susceptibility (when <50% of the isolates are susceptible to that antimicrobial). However, it is important to note that all resistance interpretations were based on isolate-level susceptibility categories using CLSI-defined breakpoints.

Table 5 Antibiogram with susceptible isolates in percentage

Organisms	No. of isolates	Amoxicillin (%)	Co-amoxiclav (%)	Ampicillin sulbactam (%)	Amikacin (%)	Gentamycin (%)	Ciprofloxacin (%)	Ofloxacin (%)	Levofloxacin (%)	Cefixime (%)	Cefotaxime (%)	Ceftriaxone (%)	Ceftazidime (%)	Cefepime (%)	Cotrimoxazole (%)	Doxycycline (%)	Tetracycline (%)	Piperacillin tazobactam (%)	Imipenem (%)	Meropenem (%)	Tigecycline (%)	Tobramycin (%)	Polymyxin B (%)	Linezolid (%)	Aztreonam (%)
Gram negative
E. coli	28	82	71	25	93	82	57	86	89	96	75	79	86	71	71	86	100	82	93	86	0	86	100	96	82
Citrobacter	22	95	86	14	77	91	73	77	82	86	77	50	91	50	50	100	100	86	95	86	100	100	100	100	68
Klebsiella	14	93	100	7	100	86	79	71	100	100	64	86	100	64	50	100	100	79	86	93	0	95	100	100	100
Pseudomonas	5								0	100	100	100	40	100	100	100		100	60	60	100	100	100	100	100
Morganella	2		100	0	100	100	50	100	100	100	50	100	40	100	50	100		100	100	100	100	100		100	100
Proteus	2		50	0	100	100	50	100	100	100	50	50	100	100	50	100		100	100	100		100		100	50
Enterobacter	1		100	0	0	100	100	0	100	100	100	100	0	0	100	100		0	0	100		100		100	100
Gram positive
Enterococcus	1		0	0	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100	100		100		100	100

Notes:

Not tested

High susceptibility (≥90%)

Intermediate susceptibility (50–89%)

Low susceptibility (<50%)

Discussion

In this cross-sectional study involving patients undergoing ERC at a tertiary-care center in Nepal, we sought to describe the microbial profile and antibiotic resistance patterns in bile cultures and compare those with and without acute cholangitis. We found a very high prevalence of positive bile cultures, with a significantly higher rate observed among patients with acute cholangitis than those without acute cholangitis. Gram-negative organisms were the predominant pathogens isolated, with Escherichia coli being the most frequent isolate. Importantly, patients with cholangitis exhibited a distinct microbial pattern, with Pseudomonas species being isolated exclusively in this group.

The high (84%) prevalence of positive bile cultures in our study aligns with several earlier studies, particularly those among the patients undergoing ERC for acute cholangitis or biliary obstruction, though there was a wide variation in the prevalence observed (50.5–96.4%) as well as the microbial profiles and their antimicrobial susceptibility patterns. Our study found a predominance of gram-negative organisms, with E. coli (38%) as the most common isolate. This is comparable to the findings from China (30.3–37.7% of E. coli, and 10.2–15.7% of Klebsiella) and Turkey (28.2% of E. coli), but is in contrast to the findings reported from the United States and Germany in which gram-positive organism Enterococcus spp. dominated in the microorganisms isolated (33–67.7%).[11] [12] [13] [14] [15] [16] [17]

This variation in microbial distribution likely reflects differences in patient populations, underlying comorbidities, prior procedures, and regional antibiotic resistance patterns. The studies from the United States and Germany primarily involved patients from high-income settings, where older age, malignancies, and prior healthcare exposure, including repeated biliary interventions such as biliary stenting and sphincterotomy, are more common. For example, the study population in the study had a higher median age (65 vs. 54.5 years).[11] Nearly one-third of the study population from the studies from the United States and Germany had underlying malignancy, as opposed to less than one-fourth of our study population.[11] [14] Similarly, nearly one-third of the study population from the other German study had orthoptic liver transplantation, reflecting underlying immunosuppression.[15] These factors are associated with a higher prevalence of Enterococcus spp., which are often nosocomial pathogens and tend to colonize patients with prolonged hospital stays, immunosuppression, or prior antibiotic exposure.[18] Our study had fewer prior biliary interventions (58% of patients had no prior biliary procedures) and a higher proportion of patients presenting with choledocholithiasis (68%) rather than malignancies. This may explain the predominance of gram-negative organisms, which are more commonly associated with community-acquired infections.[19] [20] In addition, antibiotic usage patterns, sample collection, and culture techniques, as well as healthcare infrastructure and infection control practices likely play a role as well. The predominance of gram-negative organisms in our study underscores the need for coverage against Enterobacteriaceae, and the isolation of Pseudomonas species exclusively in patients with acute cholangitis suggests anti-pseudomonal antimicrobial among these populations. In higher-income settings, however, coverage for Enterococcus spp. is recommended, in addition to that for gram-negative organisms.

Notably, the microorganisms isolated in our study demonstrated an overall higher resistance to several antimicrobials, including β-lactams, fluoroquinolones, and aminoglycosides, particularly for E. coli, Klebsiella spp., and Citrobacter spp., as compared with the several studies from both high-income and low- and middle-income settings. High rates of resistance to carbapenems were also noted in our study, particularly in Pseudomonas and Enterobacter. This contrasts with the study from the United States in which most isolates retained high susceptibility (85–100%) to key antibiotics, including ceftriaxone and ciprofloxacin, and with the study from Germany which documented moderate susceptibility (72–80%) for β-lactams and fluoroquinolones and much lower susceptibility rates in E. coli, Klebsiella spp., and Citrobacter spp. for these same antibiotics.[11] [14] Despite a similar microbial profile, antimicrobial resistance observed in our study was higher than those reported from China, especially carbapenems (7–14% vs. 1–4%), β-lactams (50–70% vs. 31–67%), and aminoglycosides (14–23% vs. 5–10%) in one study and carbapenems (7–14% vs. 2–4%) in another study.[16] [17]

Several factors could be implicated in the higher resistance rates in this study. Perhaps the most crucial is the lack of robust antimicrobial stewardship programs with controlled antimicrobial use and infection control practices in Nepal, which may limit the spread of resistant organisms. In addition, the lack of comprehensive facility-based antibiograms and institution-based protocols for the selection of antimicrobial agents for empiric treatment of infections, coupled with the availability of almost all antimicrobials over the counter, leads to increased antibiotic misuse or overuse in Nepal, contributing to selection pressure for resistant strains. These findings underscore the urgent need for better antimicrobial stewardship programs limiting inappropriate antibiotic use and infection control policies as much as for the standardized protocols for empiric antimicrobials based on the local antibiograms.

Our study highlights several important considerations for clinical practice. Though patients with acute cholangitis are more likely to have positive bile cultures, the prevalence of positive bile cultures in those without acute cholangitis remains considerable, suggesting that empiric antimicrobials could still be considered in these patient populations. Broader-spectrum agents, such as piperacillin–tazobactam or carbapenems, may be more appropriate for initial treatment, particularly in patients with acute cholangitis or other severe infections. In addition, these findings reinforce the importance of obtaining bile cultures during ERC to guide antibiotic selection and ensure appropriate antimicrobial stewardship.[8] [21] The study also reinforces the utility of routine bile culture in optimizing antibiotic management for cholangitis, although contamination during sample collection remains a limitation to be accounted for. Importantly, the detection of Pseudomonas exclusively in patients with cholangitis suggests that specific clinical features may predict the presence of certain pathogens and could be used to tailor empirical treatment. In treating acute cholangitis, however, a shorter course of antibiotics has been shown to be as effective as the conventional longer course in patients with moderate-to-severe cholangitis, supporting antibiotic stewardship without compromising clinical outcomes.[22]

Our study has several limitations. First, as a cross-sectional investigation, it does not establish a temporal relationship between microbial colonization and clinical outcomes. While the association between positive bile cultures and cholangitis is evident, the lack of longitudinal data precludes definitive conclusions about the impact of specific organisms or resistance patterns on patient prognosis. Second, our study was conducted at a single tertiary-care center in Nepal, which may limit the generalizability of the findings to other settings. The microbial profile and resistance patterns observed may reflect local epidemiologic trends and healthcare practices, which could differ significantly from those in other regions or institutions. Third, we relied on conventional microbiologic methods without molecular typing, which may limit our understanding of pathogen transmission dynamics and resistance mechanisms. Future studies should focus on larger, multicenter cohorts, particularly with longitudinal data, to validate these findings, improve generalizability, and explore causality between microbial colonization and clinical outcomes. Furthermore, investigations into the efficacy of specific antibiotic regimens based on local susceptibility patterns are also recommended.

The high rates of positive bile cultures in patients undergoing ERC, especially those with acute cholangitis, and high antibiotic resistance in the organisms isolated, found in our study, highlight the need for tailored empirical treatment and improved antimicrobial stewardship. Routine bile cultures are essential for guiding antibiotic therapy, especially in cholangitis, and should be prioritized in settings with high resistance rates.

Conflict of Interest

None declared.

Ethical Statement

Ethical clearance was obtained from the Institutional Review Board of NAMS (reference number: 1041/2080/81).

Informed Consent

All participants provided written informed consent before their inclusion in the study, with assurances of confidentiality.

Authors' Contributions

S.S. conceptualized and designed the study, collected data, performed data analysis and interpretation, and drafted the initial manuscript. B.K.B. supervised the study, contributed to study design and methodology, guided data interpretation, and revised the manuscript for important intellectual content. A.K. and N.S.P. provided critical input and revised the manuscript for important intellectual content. M.S.P. contributed to study design and methodology, guided data interpretation, and revised the manuscript for important intellectual content. All authors read and approved the final version of the manuscript. B.K.B. served as the guarantor of the work.

Data Availability Statement

The data can be obtained from the corresponding author upon a reasonable request.

• References

• 1 Csendes A, Fernandez M, Uribe P. Bacteriology of the gallbladder bile in normal subjects. Am J Surg 1975; 129 (06) 629-631
• 2 Csendes A, Burdiles P, Maluenda F, Diaz JC, Csendes P, Mitru N. Simultaneous bacteriologic assessment of bile from gallbladder and common bile duct in control subjects and patients with gallstones and common duct stones. Arch Surg 1996; 131 (04) 389-394
• 3 Shenoy SM, Shenoy S, Gopal S, Tantry BV, Baliga S, Jain A. Clinicomicrobiological analysis of patients with cholangitis. Indian J Med Microbiol 2014; 32 (02) 157-160
• 4 Kruis T, Güse-Jaschuck S, Siegmund B, Adam T, Epple HJ. Use of microbiological and patient data for choice of empirical antibiotic therapy in acute cholangitis. BMC Gastroenterol 2020; 20 (01) 65
• 5 Miura F, Okamoto K, Takada T. et al. Tokyo Guidelines 2018: initial management of acute biliary infection and flowchart for acute cholangitis. J Hepatobiliary Pancreat Sci 2018; 25 (01) 31-40
• 6 Rhodes A, Evans LE, Alhazzani W. et al. Surviving sepsis campaign: international guidelines for management of sepsis and septic shock: 2016. Crit Care Med 2017; 45 (03) 486-552
• 7 Kwon JS, Han J, Kim TW. et al. Changes in causative pathogens of acute cholangitis and their antimicrobial susceptibility over a period of 6 years. Korean J Gastroenterol 2014; 63 (05) 299-307
• 8 Negm AA, Schott A, Vonberg RP. et al. Routine bile collection for microbiological analysis during cholangiography and its impact on the management of cholangitis. Gastrointest Endosc 2010; 72 (02) 284-291
• 9 Salvador VB, Lozada MC, Consunji RJ. Microbiology and antibiotic susceptibility of organisms in bile cultures from patients with and without cholangitis at an Asian academic medical center. Surg Infect (Larchmt) 2011; 12 (02) 105-111
• 10 CLSI. Performance Standards for Antimicrobial Susceptibility Testing. Clinical and Laboratory Standards Institute; 2023
• 11 Gromski MA, Gutta A, Lehman GA. et al. Microbiology of bile aspirates obtained at ERCP in patients with suspected acute cholangitis. Endoscopy 2022; 54 (11) 1045-1052
• 12 Gu XX, Zhang MP, Zhao YF, Huang GM. Clinical and microbiological characteristics of patients with biliary disease. World J Gastroenterol 2020; 26 (14) 1638-1646
• 13 Kaya M, Beştaş R, Bacalan F, Bacaksız F, Arslan EG, Kaplan MA. Microbial profile and antibiotic sensitivity pattern in bile cultures from endoscopic retrograde cholangiography patients. World J Gastroenterol 2012; 18 (27) 3585-3589
• 14 Reiter FP, Obermeier W, Jung J. et al. Prevalence, resistance rates, and risk factors of pathogens in routine bile cultures obtained during endoscopic retrograde cholangiography. Dig Dis 2021; 39 (01) 42-51
• 15 Rupp C, Bode K, Weiss KH. et al. Microbiological assessment of bile and corresponding antibiotic treatment: a strobe-compliant observational study of 1401 endoscopic retrograde cholangiographies. Medicine (Baltimore) 2016; 95 (10) e2390
• 16 Zhang H, Cong Y, Cao L. et al. Variability of bile bacterial profiles and drug resistance in patients with choledocholithiasis combined with biliary tract infection: a retrospective study. Gastroenterol Rep (Oxf) 2024; 12: goae010
• 17 Zhao C, Liu S, Bai X, Song J, Fan Q, Chen J. A retrospective study on bile culture and antibiotic susceptibility patterns of patients with biliary tract infections. Evid Based Complement Alternat Med 2022; 2022: 9255444
• 18 Reuken PA, Torres D, Baier M. et al. Risk factors for multi-drug resistant pathogens and failure of empiric first-line therapy in acute cholangitis. PLoS One 2017; 12 (01) e0169900
• 19 Brook I. Aerobic and anaerobic microbiology of biliary tract disease. J Clin Microbiol 1989; 27 (10) 2373-2375
• 20 Gomi H, Solomkin JS, Schlossberg D. et al. Tokyo Guidelines 2018: antimicrobial therapy for acute cholangitis and cholecystitis. J Hepatobiliary Pancreat Sci 2018; 25 (01) 3-16
• 21 Chandra S, Klair JS, Soota K, Livorsi DJ, Johlin FC. Endoscopic retrograde cholangio-pancreatography-obtained bile culture can guide antibiotic therapy in acute cholangitis. Dig Dis 2019; 37 (02) 155-160
• 22 Srinu D, Shah J, Jena A. et al. Conventional vs short duration of antibiotics in patients with moderate or severe cholangitis: noninferiority randomized trial. Am J Gastroenterol 2024; 119 (01) 176-182

Publikationsverlauf

Eingereicht: 26. April 2025

Angenommen: 30. Juli 2025

Artikel online veröffentlicht:
09. Oktober 2025