Microbiologic Data in Acute Cholecystitis: Ten Years' Experience from Bile Cultures Obtained during Percutaneous Cholecystostomy

Dual-energy CT in acute cholecystitis- features predicting culture-positive bile and outcome

PURPOSE

Low mono-energetic CT has been shown to improve visualization of acute abdominal inflammatory processes. We aimed to determine its utility in patients with acute cholecystitis and potential added value in clinical decision making.

METHODS

Sixty-seven consecutive patients with radiological signs of cholecystitis on contrast-enhanced dual-layer CT imaging were retrospectively identified over a four-year period (2/17-8/21). A ranked Likert scale was created for imaging findings present in acute cholecystitis, including gallbladder mucosal integrity and enhancement and pericholecystic liver parenchymal enhancement. These rankings were correlated with laboratory data, followed by sensitivity, specificity, and odds-ratios calculations.

RESULTS

Mucosal integrity and pericholecystic liver enhancement were better seen on low-energetic images by unanimous consensus. Presence of pericholecystic liver enhancement and poorer mucosal wall integrity correlated with positive bile cultures (sensitivity: 93.8 % and 96.9 %, specificity: 37.5 and 50.0 %; odds-ratio: 9.0[1.1-68.1 95 %CI] and 31.0 [2.7-350.7 95 %CI], p = 0.017 and p ≤ 0.001) in patients undergoing cholecystostomy (n = 40/67). Moreover, binary regression modeling showed that the strongest predictor variable for bile culture positivity was the score for pericholecystic liver enhancement (Exp(B) = 0.6, P = 0.022). By contrast, other laboratory markers and other imaging findings (such as GB wall thickness) showed lower sensitivities (76-82 %), specificities (16-21 %) and odds ratios (0.2-4.4) for the prediction of infected bile.

CONCLUSIONS

Pericholecystic liver enhancement and gallbladder wall integrity are better visualized on low-DECT images. These findings also potentially predict bile culture positivity in patients with cholecystitis, which may influence clinical management including the need for intervention.

Laparoscopic cholecystectomy in calculous cholecystitis: are antibiotics necessary?

Laparoscopic cholecystectomy in patients with cholecystitis is considered the best, appropriate and safe method of treatment for gallstone disease. However, the role of antibiotic administration before or after cholecystectomy to reduce infectious complications, particularly surgical site infections, or mortality is less clear. Many patients receive empiric antibiotics, but the feasibility of their use has not been proven. Some guidelines suggest the use of antibiotic prophylaxis for all cholecystectomies, although current evidence does not indicate any benefit to this practice in the absence of risk factors. This review examines the results of antibiotic use in laparoscopic cholecystectomy for chronic and acute calculous cholecystitis. Most studies argue against the need to use prophylactic antibiotics during elective surgery in low-risk patients. In cases of mild and moderate acute cholecystitis, the use of antibiotics to prevent postoperative infectious complications has no evidence of effectiveness, although these recommendations are also ambiguous. It is not recommended to use postoperative antibiotics after elective laparoscopic cholecystectomy, as well as for mild or moderate acute cholecystitis. However, additional studies with well-defined patient populations and comparable outcomes are needed to better assess the most appropriate timing and duration of antibiotic use in patients undergoing laparoscopic cholecystectomy. We used MedLine database on the PubMed platform and the Cochrane library to search for literature sources.

Impact of empiric antibiotic therapy on the clinical outcome of acute calculous cholecystitis

PURPOSE

Although mortality and morbidity of severe acute calculous cholecystitis (ACC) are still a matter of concern, the impact of inadequate empirical antibiotic therapy has been poorly studied as a risk factor. The objective was to assess the impact of the adequacy of empirical antibiotic therapy on complication and mortality rates in ACC.

METHODS

This observational retrospective cohort chart-based single-center study was conducted between 2012 and 2016. A total of 963 consecutive patients were included, and pure ACC was selected. General, clinical, postoperative, and microbiological variables were collected, and risk factors and consequences of inadequate treatment were analyzed.

RESULTS

Bile, blood, and/or exudate cultures were obtained in 76.3% of patients, more often in old, male, and severely ill patients (P < 0.001). Patients who were cultured had a higher overall rate of postoperative complications (47.4% vs. 29.7%; P < 0.001), as well as of severe complications (11.6% vs. 4.7%; P = 0.008). Patients with positive cultures had more overall complications (54.8% vs. 39.6%; P = 0.001), more severe complications (16.3% vs. 6.7%; P = 0.001), and higher mortality rates (6% vs. 1.9%; P = 0.012). Patients who received inadequate empirical antibiotic therapy had a fourfold higher mortality rate than those receiving adequate therapy (n = 283; 12.8% vs. 3.4%; P = 0.003). This association was especially marked in severe ACC TG-III patients (n = 132; 18.2 vs. 5.1%; P = 0.018) and remained a predictor of mortality in a binary logistic regression (OR 4.4; 95% CI 1.3-15.3).

CONCLUSION

Patients with positive cultures developed more complications and faced higher mortality. Adequate empirical antibiotic therapy appears to be of paramount importance in ACC, particularly in severely ill patients.

A Six-Year Retrospective Study of Microbiological Characteristics and Antimicrobial Resistance in Specimens from a Tertiary Hospital’s Surgical Ward

Surgery has revolutionized the practice of medicine by allowing the treatment of conditions amenable to conservative medical management with some of them pathophysiologically involving the prevalence of pathogenic microorganisms. On the other hand, infections such as surgical site infections or urinary tract infections may complicate patients hospitalized in surgical wards leading to considerable morbidity, mortality, and increased healthcare-associated costs. The aim of this study was to present the microbiological characteristics and antimicrobial resistance of all isolates identified in microbiological specimens from a surgical ward of a tertiary hospital in Greece during a six-year period. Only specimens that yielded at least one microorganism were included in the analysis. In total, 1459 strains in 789 positive cultures were isolated. The most common sample sent to the microbiology department was pus from surgical wounds. The most common pathogens among all 1459 strains isolated were Enterobacterales at 33% (n = 482), however, the most common genus was Enterococcus at 22.3% (n = 326). Antimicrobial resistance against third-generation cephalosporins was 23% (n = 111/482) among Enterobacterales, while, the rate of vancomycin-resistant enterococci (VRE) was 18.5% (n = 60/324) among Enterococcus species and was increasing in the last years of the study. Antimicrobial resistance of Acinetobacter baumannii to carbapenems was 68.8% (n = 11/16), which was lower than the corresponding rate in other wards in Greece. The antimicrobial resistance rates noted herein raise questions regarding the appropriateness of currently suggested antimicrobials in guidelines and imply that a revision could be required. Practicing clinicians should always be aware of local microbiological data that allow the selection of appropriate antimicrobials for the management of infections. Finally, the increasing rates of VRE noted herein mandate further actions from the point of infection control and antimicrobial stewardship.

Incidence of bactibilia and related factors in patients who undergo cholecystectomy

Purpose

In general, bile is normally sterile. However, there are reports bactibilia may occur in certain instances, though the causal factors are unclear. We analyzed possible preoperative predictors of bactibilia upon cholecystectomy.

Methods

Bile samples were collected during cholecystectomies from November 2018 to November 2019. A total of 428 open or laparoscopic cholecystectomies were performed. Preoperative, intraoperative, and postoperative variables were compared between the culture-positive and culture-negative groups.

Results

One hundred fifty-seven patients (36.7%) were culture-positive. Gram-negative bacteria (95 [61.0%]) were more common. Escherichia coli (38 [40.0%]) and Enterobacter (22 [23.2%]) were the most common species. In univariate analysis, age of ≥70 years (P < 0.001), male sex (P < 0.001), high American Society of Anesthesiologists physical status grades (P = 0.001), diabetes mellitus (P = 0.002), jaundice (P = 0.007), high Tokyo Guideline grades (P = 0.008), percutaneous transhepatic gallbladder drainage (PTGBD; P < 0.001), endoscopic retrograde cholangiopancreatography (ERCP; P < 0.001) were identified as a risk factors for bactibilia. In multivariate analysis, age of ≥70 years (hazard ratio [HR], 2.874; 95% confidence interval [CI], 1.769-4.670; P = 0.001), ERCP (HR, 9.001; 95% CI, 4.833-16.75; P < 0.001), and PTGBD (HR, 2.866; 95% CI, 1.440-4.901; P = 0.002) were independent risk factors for bactibilia.

Conclusion

Among patients who underwent cholecystectomy, those who were elderly, symptomatic, and underwent preoperative drainage were more likely to have bactibilia. In such cases, surgeons should take care to prevent bile leakage during surgery and consider administering appropriate antibiotics.

A Retrospective Study on Bile Culture and Antibiotic Susceptibility Patterns of Patients with Biliary Tract Infections

Aim

This study aimed to provide profiles of microorganisms isolated from bile and antibiotic susceptibility patterns of biliary tract infections (BTIs) in our center.

Methods

A total of 277 patients diagnosed with BTIs at the Second Affiliated Hospital of Harbin Medical University from 2011 to 2018 were included in this study. Medical records were reviewed to obtain clinical and demographic data. Bile specimens were prepared through endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiodrainage (PTCD), and percutaneous transhepatic gallbladder drainage (PTGD) under aseptic conditions. In those with positive bile culture results, blood cultures were concurrently conducted. The concordance of the results between bile culture and blood culture were also analysed.

Results

Two hundred and sixty-seven bile cultures were positive, while 280 strains of micro-organisms were isolated. Among these, 76.8% were Gram-negative, 22.5% were Gram-positive and 0.7% were fungi. The most common microorganisms were Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecalis. Gram-negative bacteria we tested were highly sensitive to ertapenem, imipenem, tigecycline, and amikacin. Gram-positive bacteria we tested were highly sensitive to tigecycline, teicoplanin, linezolid, vancomycin, and chloramphenicol. For the 44 patients with positive bile cultures, a blood culture was also performed. Among them, 29 cases yielded positive blood culture results. Among those cases with positive blood culture, 48.3% showed complete agreement with bile culture, 3.4% showed partial agreement, and 48.3% showed disagreement. The most common microorganisms in blood culture were the same as in bile culture. Additionally, the proportion of Staphylococcus epidermidis was significantly higher in blood culture (P < 0.05).

Conclusion

Our study provided a comprehensive analysis of the bacteria distribution and drug resistance profiles in patients with BTIs in northern China. Further studies should be conducted to validate our findings.

Targeted Metagenomic Sequencing-Based Approach Applied to 2,146 Tissue and Body Fluid Samples in Routine Clinical Practice

BACKGROUND

The yield of next generation sequencing (NGS) added to a Sanger sequencing-based 16S ribosomal RNA (rRNA) gene PCR assay was evaluated in clinical practice for diagnosis of bacterial infection.

METHODS

PCR targeting the V1 to V3 regions of the 16S rRNA gene was performed, with amplified DNA submitted to Sanger sequencing and/or NGS (Illumina MiSeq), or reported as negative, depending on cycle threshold (Ct) value. 2,146 normally sterile tissues or body fluids were tested between August 2020 and March 2021. Clinical sensitivity was assessed in 579 subjects from whom clinical data was available.

RESULTS

Compared to Sanger sequencing alone (400 positive tests), positivity increased by 87% by adding NGS (347 added positive tests). Clinical sensitivity of the assay incorporating NGS was 53%, higher than culture (42%, p<0.001), with an impact on clinical decision-making in 14% of infected cases. Clinical sensitivity in the subgroup receiving antibiotics at sampling was 41% for culture and 63% for the sequencing assay (p<0.001).

CONCLUSION

Adding NGS to Sanger sequencing of the PCR-amplified 16S rRNA gene substantially improved test positivity. In the patient population studied, the assay was more sensitive than culture, and especially so in patients who had received antibiotic therapy.

Cultivation and Genomic Characterization of the Bile Bacterial Species From Cholecystitis Patients

The microbes in human bile are closely related to gallbladder health and other potential disorders. Although the bile microbial community has been investigated by recent studies using amplicon or metagenomic sequencing technologies, the genomic information of the microbial species resident in bile is rarely reported. Herein, we isolated 138 bacterial colonies from the fresh bile specimens of four cholecystitis patients using a culturome approach and genomically characterized 35 non-redundant strains using whole-genome shotgun sequencing. The bile bacterial isolates spanned 3 classes, 6 orders, 10 families, and 14 genera, of which the members of Enterococcus, Escherichia-Shigella, Lysinibacillus, and Enterobacter frequently appeared. Genomic analysis identified three species, including Providencia sp. D135, Psychrobacter sp. D093, and Vibrio sp. D074, which are not represented in existing reference genome databases. Based on the genome data, the functional capacity between bile and gut isolates was compared. The bile strains encoded 5,488 KEGG orthologs, of which 4.9% were specific to the gut strains, including the enzymes involved in biofilm formation, two-component systems, and quorum-sensing pathways. A total of 472 antibiotic resistance genes (ARGs) were identified from the bile genomes including multidrug resistance proteins (42.6%), fluoroquinolone resistance proteins (12.3%), aminoglycoside resistance proteins (9.1%), and β-lactamase (7.2%). Moreover, in vitro experiments showed that some bile bacteria have the capabilities for bile salt deconjugation or biotransformation (of primary bile acids into secondary bile acids). Although the physiological or pathological significance of these bacteria needs further exploration, our works expanded knowledge about the genome, diversity, and function of human bile bacteria.

Empirical antibiotics for acute cholecystitis-what generation of antibiotics is an appropriate choice? A prospective, randomized controlled study

BACKGROUND

In cases of acute cholecystitis (AC), empirical antibiotics are used to prevent infectious morbidities following cholecystectomy. However, there are still no exact guidelines on which antibiotics to use.

METHODS

We enrolled 300 patients who had been admitted for cholecystectomy because of grade I or II AC. We randomly allocated them to one of two groups empirically: the first group was to be given first-generation cephalosporins (group I, 150 patients) and the second group was to be given second-generation cephalosporins (group II, 150 patients). We analyzed the clinical outcomes and the incidence of postoperative infectious morbidities.

RESULTS

The incidence rate of overall infectious morbidities (18 cases, 12% in group I; 17 cases, 11.3% in group II; P = .859) showed no difference between the two groups. The incidence rate of sepsis (only one case, 0.7% in group II, P = 1.000) or surgical site infection (nine cases, 6% in group I and eight cases, 5.3% in group II, P = 1.000) were also similar in both groups.

CONCLUSIONS

The empirical use of first-generation cephalosporins for mild-to-moderate AC without gallbladder perforation was not inferior to using second-generation cephalosporin for prophylaxis against postoperative infection. Our results could allow for a tailored treatment strategy of empirical antibiotics according to the severity of the cholecystitis.

The Great ESKAPE: Exploring the Crossroads of Bile and Antibiotic Resistance in Bacterial Pathogens

Throughout the course of infection, many pathogens encounter bactericidal conditions that threaten the viability of the bacteria and impede the establishment of infection. Bile is one of the most innately bactericidal compounds present in humans, functioning to reduce the bacterial burden in the gastrointestinal tract while also aiding in digestion. It is becoming increasingly apparent that pathogens successfully resist the bactericidal conditions of bile, including bacteria that do not normally cause gastrointestinal infections. This review highlights the ability of Enterococcus, Staphylococcus, Klebsiella, Acinetobacter, Pseudomonas, Enterobacter (ESKAPE), and other enteric pathogens to resist bile and how these interactions can impact the sensitivity of bacteria to various antimicrobial agents. Given that pathogen exposure to bile is an essential component to gastrointestinal transit that cannot be avoided, understanding how bile resistance mechanisms align with antimicrobial resistance is vital to our ability to develop new, successful therapeutics in an age of widespread and increasing antimicrobial resistance.

Antibiotic prophylaxis in acute cholecystectomy revisited: results of a double-blind randomised controlled trial

Purpose

Evidence supporting the value of preoperative antibiotic prophylaxis (PAP) in surgery for acute cholecystitis is lacking. This study aimed to shed light on whether PAP in acute cholecystectomy for cholecystitis reduces the postoperative infectious complication (PIC) rate. Secondary outcomes were the prevalence of bacteriobilia, CRP values and leucocyte counts.

Methods

The study was performed as a single-centre, double-blinded, placebo-controlled, randomised study. Patients with acute cholecystitis amenable for acute laparoscopic cholecystectomy were randomly assigned to either PAP (piperacillin/ tazobactam) or placebo, and the subsequent clinical course was followed.

Results

A total of 106 patients were enrolled, 16 of whom were excluded due to protocol violation. PIC developed in 22 of the 90 patients included with no significant difference between the PAP and placebo groups (8 patients in the PAP group and 14 in the placebo arm, p = 0.193). The PIC rate was significantly higher in patients with a raised CRP at randomisation and on the day of surgery and in cases of conversion to an open procedure (p = 0.008, 0.004 and 0.017, respectively) but with no differences between the study groups.

Conclusion

PAP does not affect the risk for PIC in patients with acute cholecystitis. The major risk factors determining PIC in these patients need defining, in particular, the impact of bacteriobilia.

Trial registration

The study was registered at clinicaltrials.gov (NCT02619149) December 2, 2015.

Antibiotic use in patients with acute cholecystitis after percutaneous cholecystostomy

BACKGROUND

Currently, evidence regarding the strategies of antibiotic use in patients with acute cholecystitis after receiving percutaneous cholecystostomy is limited. Hence, we aimed to investigate the outcomes in patients with inoperable acute cholecystitis receiving narrow or broad-spectrum antibiotics after percutaneous cholecystostomy.

METHODS

A total of 117 patients receiving percutaneous cholecystostomy were categorized into moderate and severe acute cholecystitis defined by the Tokyo guideline and then divided into group A (narrow-spectrum antibiotic use) and group B (broad-spectrum antibiotic use). The clinical outcomes and complications were analyzed.

RESULTS

In moderate acute cholecystitis (n = 80), group A patients (n = 62) had similar early recurrent rate (11.3% vs 16.7%; p = 0.544) and a shorter length of hospital stay (13.4 ± 8.6 vs 18.6 ± 9.4 days; p = 0.009) as compared with group B patients (n = 18). No in-hospital mortality occurred in moderate acute cholecystitis. In severe acute cholecystitis (n = 37), both groups had similar length of hospital stay (16.3 ± 12.2 vs 20.9 ± 9.5 days; p = 0.051), early recurrent rate (0% vs 16.7%; p = 0.105), and in-hospital mortality rate (5.3% vs 16.7%; p = 0.340). Although group B patients with severe cholecystitis had higher serum levels of alkaline phosphatase (Alk-P) and higher proportion of underlying malignancy, American Society of Anesthesiologists (ASA) class IV and septic shock, the clinical outcomes were not inferior to patients in group A.

CONCLUSION

In moderate acute cholecystitis after percutaneous cholecystostomy, patients receiving narrow-spectrum antibiotics have comparable clinical outcomes as those treated with broad-spectrum antibiotics. However, in severe acute cholecystitis, broad-spectrum antibiotics might still be necessary to rescue these patients.

Bacteria and fungi in acute cholecystitis. A prospective study comparing next generation sequencing to culture

OBJECTIVES

Guidelines for antibiotic treatment of acute cholecystitis are based on studies using culture techniques for microbial identification. Microbial culture has well described limitations and more comprehensive data on the microbial spectrum may support adjustments of these recommendations. We used next generation sequencing to conduct a thorough microbiological characterization of bile-samples from patients with moderate and severe acute cholecystitis.

METHODS

We prospectively included patients with moderate and severe acute cholecystitis, undergoing percutaneous or perioperative drainage of the gall bladder. Bile samples were analyzed using both culture and deep sequencing of bacterial 16S rRNA and rpoB genes and the fungal ITS2-segment. Clinical details were evaluated by medical record review.

RESULTS

Thirty-six patients with moderate and severe acute cholecystitis were included. Bile from 31 (86%) of these contained bacteria (29) and/or fungi (5) as determined by sequencing. Culture identified only 40 (38%) of the 106 microbes identified by sequencing. In none of the 15 polymicrobial samples did culture detect all present microbes. Frequently identified bacteria often missed by culture included oral streptococci, anaerobic bacteria, enterococci and Enterobacteriaceae other than Klebsiella spp. and Escherichia coli.

CONCLUSIONS

Culture techniques display decreased sensitivity for the microbial diagnostics of acute cholecystitis leaving possible pathogens undetected.

The appropriateness of ceftriaxone and metronidazole as empirical therapy in managing complicated intra-abdominal infection-experience from Western Health, Australia

Purpose

This study aims to assess the microbiological profile, antimicrobial susceptibility and adequacy of intravenous ceftriaxone and metronidazole as empirical therapy for surgical patients presenting with complicated intra-abdominal infection.

Methods

This retrospective audit reviews the microbiological profile and sensitivity of intra-abdominal cultures from adult patients with complicated intra-abdominal infection who presented to the emergency department at Western Health (Melbourne, Australia) between November 2013 and June 2017. Using the hospital’s database, an audit was completed using diagnosis related group (DRG) coded data. Ethics approval has been granted by the Western Health Human Research Ethics Committee. Results are stratified according to surgical conditions (appendicitis, cholecystitis, sigmoid diverticulitis and bowel perforation). The antimicrobial coverage of ceftriaxone and metronidazole is evaluated against these microbial profiles.

Results

A total of 1,412 patients were identified using DRG codes for intra-abdominal infection. All patients with microscopy and sensitivity results were included in the study. Patients without these results were excluded. 162 patients were evaluable. 180 microbiological cultures were performed through surgical intervention or radiologically guided aspiration of the intra-abdominal infection. Single or multiple pathogens were identified in 137 cultures. The most commonly identified pathogens were mixed anaerobes (12.6%), Escherichia coli (E. coli) (12.1%), mixed coliforms (11.6%) and Pseudomonas aeruginosa (7%). Other common pathogens (6% each) included Enterococcus faecalis, Streptococcus anginosus, Vancomycin-resistant Enterococci (VRE) and Extended Spectrum Beta-Lactamases (ESBL) producing E. coli. Organisms isolated in our study are consistent with existing literature. However, a significant proportion of antibiotic resistant organisms was identified in cases of perforated bowel and sigmoid diverticulitis. Broader spectrum antimicrobial therapy should therefore be considered in lieu of ceftriaxone and metronidazole in these cases. Ceftriaxone and metronidazole remain as appropriate empirical therapy for patients who presented with perforated appendicitis and cholecystitis.

Discussion

The empirical regime of ceftriaxone and metronidazole remains appropriate for intra-abdominal infection secondary to appendicitis and cholecystitis. In cases involving perforated small and large bowel, including complicated sigmoid diverticulitis, the judicious use of ceftriaxone and metronidazole is recommended.