Two cases of monomicrobial intraabdominal abscesses due to KPC--3 Klebsiella pneumoniae ST258 clone

Comparative phenotypic and genotypic analysis of community-acquired and hospital-acquired intra-abdominal infections among liver transplanted patients

AIM

During liver transplantation, both hospital-acquired (HA) and community-acquired (CA) intra-abdominal infections (IAIs) are involved causing life-threatening diseases. Therefore, comparative studies of aerobic and facultative anaerobic HA-IAIs and CA-IAIs after liver transplantation surgery are necessary.

METHODS AND RESULTS

The species of detected isolates (310) from intra-abdominal fluid were identified and classified into hospital-acquired intra-abdominal infections (HA-IAIs) and community-acquired intra-abdominal infections (CA-IAIs). Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii were the most commonly detected species. The resistant phenotypes were commonly detected among the HA-IAIs; however, the virulent phenotypes were the predominant strains of CA-IAIs. Regrettably, the resistance profiles were shocking, indicating the inefficacy of monotherapy in treating these isolates. Therefore, we confirmed the use of empirical combination therapies of amikacin and meropenem for treating all IAIs (FICI ≤ 0.5). Unfortunately, the high diversity and low clonality of all identified HA and CA-IAIs were announced with D-value in the range of 0.992-1.

CONCLUSION

This diversity proves that there are infinite numbers of infection sources inside and outside healthcare centers.

Thrombocytopenia in Klebsiella pneumoniae liver abscess: a retrospective study on its correlation with disease severity and potential causes

Objective

Thrombocytopenia is commonly associated with infectious diseases and serves as an indicator of disease severity. However, reports on its manifestation in conjunction with Klebsiella pneumoniae liver abscess (KPLA) are scarce. The present study sought to elucidate the correlation between thrombocytopenia and KPLA severity and delve into the etiological factors contributing to the incidence of thrombocytopenia.

Materials and methods

A retrospective analysis of the clinical data from patients with KPLA admitted between June 2012 and June 2023 was performed. Baseline characteristics, biochemical assessments, therapeutic interventions, complications, and clinical outcomes were compared between patients with and without thrombocytopenia. To investigate the potential etiologies underlying thrombocytopenia, the association between platelet count reduction and thrombophlebitis was examined, with a particular focus on platelet consumption. Furthermore, bone marrow aspiration results were evaluated to assess platelet production anomalies.

Results

A total of 361 KPLA patients were included in the study, among whom 60 (17%) had concurrent thrombocytopenia. Those in the thrombocytopenia group exhibited significantly higher rates of thrombophlebitis (p = 0.042), extrahepatic metastatic infection (p = 0.01), septic shock (p = 0.024), admissions to the intensive care unit (p = 0.002), and in-hospital mortality (p = 0.045). Multivariate analysis revealed that thrombocytopenia (odds ratio, 2.125; 95% confidence interval, 1.114-4.056; p = 0.022) was independently associated with thrombophlebitis. Among the thrombocytopenic patients, eight underwent bone marrow aspiration, and six (75%) had impaired medullar platelet production. After treatment, 88.6% of thrombocytopenic patients (n = 47) demonstrated recovery in their platelet counts with a median recovery time of five days (interquartile range, 3-6 days).

Conclusions

Thrombocytopenia in patients with KPLA is indicative of increased disease severity. The underlying etiologies for thrombocytopenia may include impaired platelet production within the bone marrow and augmented peripheral platelet consumption as evidenced by the presence of thrombophlebitis.

Clinical characteristics and outcome of patients with enterococcal liver abscess

Epidemiology of bacteria isolated from pyogenic liver abscesses change, and an increase in enterococci has been reported in European hospitals. The aim of this study was to investigate the clinical characteristics and outcome of enterococcal PLA. We performed a retrospective analysis of patients with microbiologically confirmed PLA at three German university centers. Indicators of enterococcal PLA were determined using binary logistic regression, and survival analysis was performed using Kaplan-Meier statistics and Cox regression analysis. Enterococci were isolated in 51/133 (38%) patients with PLA. Patients with enterococcal PLA had smaller abscess diameter (4.8 vs. 6.7 cm, p = 0.03) than patients with non-enterococcal PLA, but had more frequent polymicrobial culture results. In univariate logistic regression analysis, alcohol abuse (OR 3.94, 95% CI 1.24-12.49, p = 0.02), hepatobiliary malignancies (OR 3.90, 95% CI 1.86-8.18, p < 0.001) and cirrhosis (OR 6.36, 95% CI 1.27-31.96, p = 0.02) were associated with enterococcal PLA. Patients with enterococcal PLA had a higher mortality than patients with non-enterococcal PLA (hazard ratio 2.92; 95% confidence interval 1.09-7.80; p = 0.03), which remained elevated even after excluding patients with hepatobiliary malignancies, cirrhosis, and transplant recipients in a sensitivity analysis. The increased mortality was associated with non-fecal enterococci but not in patients with Enterococcus faecalis. In this retrospective, multicenter study, enterococcal PLA was common and indicated an increased risk of mortality, underscoring the need for close clinical monitoring and appropriate treatment protocols in these patients.

Risk Factors for Intra-Abdominal Infections Caused by Carbapenemase-Producing Enterobacteriaceae in a Surgical Setting

Background: The aim of this study was to identify risk factors for acquisition of intra-abdominal infections (IAI) caused by carbapenemase-producing Enterobacteriaceae (CPE) in surgical patients. Methods: A matched case-control study was performed. We included all cases with CPE-related IAI acquired during admission to a general surgery department from January 2013 to December 2018, and they were matched with control subjects with IAI caused by non-resistant bacteria (ratio 1:3). Independent risk factors were obtained by logistic regression. Results: Forty patients with IAI-CPE were matched with 120 control subjects. Independent risk factors for acquisition of IAI-CPE were previous hospitalization (odds ratio [OR] 2.56; 95% confidence interval [CI] l 1.01-6.49; p = 0.047), digestive endoscopy (OR 4.11; 95% CI 1.40-12.07; p = 0.010), carbapenem therapy (OR 9.54; 95% CI 3.33-27.30; p < 0.001), and aminoglycoside use (OR 45.41; 95% CI 7.90-261.06; p < 0.001). Conclusions: Four clinical factors can identify patients at high-risk of IAI-CPE.

Human bile microbiota: A retrospective study focusing on age and gender

AIMS

The emerging biliary colonization of microorganisms in patients with biliary diseases may be devastating. Recent evidence suggests that age and gender may influence changes in the microbial composition of gut microbiota. To study the relationship between these parameters on bile microbiota, we retrospectively reviewed positive bile cultures following an endoscopic retrograde cholangiopancreatography (ERCP) in a QA-certified academic surgical unit of a single institution.

METHODS

449 positive bile cultures from 172 Italian patients with diseases of the biliopancreatic system hospitalized from 2006 through 2017 were investigated for aerobic, anaerobic, and fungal organisms. The patients were stratified into four age intervals (22-66, 67-74, 75-81, and 82-93 years) and followed up for five years.

RESULTS

Gram-positive bacteria (GPB) was negatively associated with age only in multivariate analysis (R_partial = -0.114, p = 0.017), with younger patients prone to harbor GPB and older patients likely to have Gram-negative bacteria (GNB). There was a definite link with the male gender using both univariate and multivariate analysis (p < 0.001). Enterococcus spp. was the most common strain identified in patients with GPB except for patients aged 67-74 years for male (95.2%) and female (80.9%) patients. Escherichia coli and Klebsiella spp. were most frequent than others in every group analyzed. Analogous results were found for bacteria Non-fermenting Gram-negative bacilli (NFGNB), such as Pseudomonas spp. and Stenotrophomonas spp. apart of the 2nd quartile.

CONCLUSIONS

Our study strengthens the bond of age and gender with bile microbiota composition and suggests that further investigations may be required in targeting the aging microbiome. Other studies should also focus on Mediterranean epidemiological characteristics and antibiotic resistance surveillance system strategies.

Emerging high-risk ST101 and ST307 carbapenem-resistant Klebsiella pneumoniae clones from bloodstream infections in Southern Italy

BACKGROUND

Carbapenem-resistant Klebsiella pneumoniae (CR-KP) is an urgent public health issue in Italy. This pattern of resistance is due mainly to dissemination of carbapenemase genes. Molecular characterization of carbapenem-resistant Klebsiella pneumoniae (CR-KP) strains was performed over a three-year period. In-depth analysis was performed on a subset of emerging CR-KP ST101 and ST307 clones.

METHODS

A prospective study was performed on 691 patients with CR-KP bloodstream infections hospitalized in 19 hospitals located in three large provinces in Southern Italy. Carbapenemase genes were identified via genotyping methods. Multi-locus sequence typing (MLST) and Whole Genome Sequencing (WGS) were carried out on ST101 and ST307 isolates.

RESULTS

Among the CR-KP isolates, bla_KPC was found in 95.6%, bla_VIM was found in 3.5%, bla_NDM was found in 0.1% and bla_OXA-48 was found in 0.1%. The bla_KPC-3 variant was identified in all 104 characterized KPC-KP isolates. MLST of 231 representative isolates revealed ST512 in 45.5%, ST101 in 20.3% and ST307 in 18.2% of the isolates. cgMLST of ST307 and ST101 isolates revealed presence of more than one beta-lactam resistance gene. Amino acid substitution in the chromosomal colistin-resistance gene pmrB was found in two ST101 isolates.

CONCLUSIONS

ST512 is widespread in Southern Italy, but ST101 and ST307 are emerging since they were found in a significant proportion of cases. Aggressive infection control measures and a continuous monitoring of these high-risk clones are necessary to avoid rapid spread of CR-KP, especially in hospital settings.

Calculated parenteral initial treatment of bacterial infections: Intra-abdominal infections

This is the seventh chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The chapter deals with the empirical and targeted antimicrobial therapy of complicated intra-abdominal infections. It includes recommendations for antibacterial and antifungal treatment.

Co-existence of virulence factors and antibiotic resistance in new Klebsiella pneumoniae clones emerging in south of Italy

Background

Endemic presence of Klebsiella pneumoniae resistant to carbapenem in Italy has been due principally to the clonal expansion of CC258 isolates; however, recent studies suggest an ongoing epidemiological change in this geographical area.

Methods

50 K. pneumoniae strains, 25 carbapenem-resistant (CR-Kp) and 25 susceptible (CS-Kp), collected from march 2014 to march 2016 at the Laboratory of Bacteriology of the Paolo Giaccone Polyclinic University hospital of Palermo, Italy, were characterized for antibiotic susceptibility and fully sequenced by next generation sequencing (NGS) for the in silico analysis of resistome, virulome, multi-locus sequence typing (MLST) and core single nucleotide polymorphism (SNP) genotypes

Results

MLST in silico analysis of CR-Kp showed that 52% of isolates belonged to CC258, followed by ST395 (12%), ST307 (12%), ST392 (8%), ST348 (8%), ST405 (4%) and ST101 (4%). In the CS-Kp group, the most represented isolate was ST405 (20%), followed by ST392 and ST15 (12%), ST395, ST307 and ST1727 (8%). The in silico β-lactamase analysis of the CR-Kp group showed that the most detected gene was blaSHV (100%), followed by blaTEM (92%), blaKPC (88%), blaOXA (88%) and blaCTX-M (32%). The virulome analysis detected mrk operon in all studied isolates, and wzi-2 was found in three CR-Kp isolates (12%). Furthermore, the distribution of virulence genes encoding for the yersiniabactin system, its receptor fyuA and the aerobactin system did not show significant distribution differences between CR-Kp and CS-Kp, whereas the Klebsiella ferrous iron uptake system (kfuA, kfuB and kfuC genes), the two-component system kvgAS and the microcin E495 were significantly (p < 0.05) prevalent in the CS-Kp group compared to the CR-Kp group.

Core SNP genotyping, correlating with the MLST data, allowed greater strain tracking and discrimination than MLST analysis.

Conclusions

Our data support the idea that an epidemiological change is ongoing in the Palermo area (Sicily, Italy). In addition, our analysis revealed the co-existence of antibiotic resistance and virulence factors in CR-Kp isolates; this characteristic should be considered for future genomic surveillance studies.

The microbiota of the bilio-pancreatic system: a cohort, STROBE-compliant study

Background: The gut microbiota play an essential role in protecting the host against pathogenic microorganisms by modulating immunity and regulating metabolic processes. In response to environmental factors, microbes can hugely alter their metabolism. These factors can substantially impact the host and have potential pathologic implications.  Particularly pathogenic microorganisms colonizing pancreas and biliary tract tissues may be involved in chronic inflammation and cancer evolution.

Purpose: To evaluate the effect of bile microbiota on survival in patients with pancreas and biliary tract disease (PBD).

Patients and Methods: We investigated 152 Italian patients with cholelithiasis (CHL), cholangitis (CHA), cholangiocarcinoma (CCA), gallbladder carcinoma (GBC), pancreas head carcinoma (PHC), ampullary carcinoma (ACA), and chronic pancreatitis (CHP). Demographics, bile cultures, therapy, and survival rates were analyzed in cohorts (T₁ death <6 months; T₂ death <12 months; T₃ death <18 months, T_3S alive at 18 months).

Results: The most common bacteria in T₁ were E. coli, K. pneumoniae, and P. aeruginosa. In T₂, the most common bacteria were E. coli and P. aeruginosa. In T₃, there were no significant bacteria isolated, while in T_3S the most common bacteria were like those found in T₁. E. coli and K. pneumoniae were positive predictors of survival for PHC and ACA, respectively. E. coli, K. pneumoniae, and P. aeruginosa showed a high percentage of resistant bacteria to 3CGS, aminoglycosides class, and quinolone group especially at T₁ and T₂ in cancer patients.

Conclusions: An unprecedented increase of E. coli in bile leads to a decrease in survival. We suggest that some strains isolated in bile samples may be considered within the group of risk factors in carcinogenesis and/or progression of hepato-biliary malignancy. A better understanding of bile microbiota in patients with PBD should lead to a multifaceted approach to rapidly detect and treat pathogens before patients enter the surgical setting in tandem with the implementation of the infection control policy.

Ertapenem non-susceptibility and independent predictors of the carbapenemase production among the Enterobacteriaceae isolates causing intra-abdominal infections in the Asia-Pacific region: results from the Study for Monitoring Antimicrobial Resistance Trends (SMART)

Objectives

This study investigated the prevalence rates of carbapenemase positivity, antibiotic susceptibility, and independent predictors of carbapenemase producers among the Enterobacteriaceae isolates recovered from patients with intra-abdominal infections (IAI) in the Asia-Pacific region between 2008 and 2014.

Materials and methods

Multiplex PCR was used for the detection of specific β-lactamases, while the broth microdilution method was used to determine the minimum inhibitory concentrations (MICs) of antibiotics among the IAI-related Enterobacteriaceae isolates. We studied the abovementioned parameters in 484 ertapenem-non-susceptible (Erta-NS) isolates and explored the independent predictors of carbapenemase-producing Enterobacteriaceae (CPE) isolates.

Results

Eighty (16.5%) Erta-NS-IAI Enterobacteriaceae isolates were found to be CPE. Vietnam and the Philippines had the highest CPE prevalence rates. The IAI isolates of Enterobacter species and Klebsiella pneumoniae followed by Escherichia coli were the three major pathogens with 77.4%, 40.9%, and 11.7% Erta-NS prevalence rates, respectively. Furthermore, the highest CPE prevalence (35%) was noted among the Erta-NS-K. pneumoniae isolates. The CPE isolates harboring the bla_NDM, bla_KPC, or blaOXA-48-like alleles had higher imipenem MIC levels than those harboring the bla_IMP alleles. Using multivariate logistic regression analysis, we concluded that Erta-NS-IAI isolates with an imipenem non-susceptible phenotype (OR, 56.4), with cefepime MIC >8 µg/mL (OR, 4.4), cultured from the peritoneal space samples (tissue or abscess; OR, 3.3), and harboring the extended-spectrum β-lactamase encoding allele (OR, 11.5) are independent predictors of CPE.

Conclusion

Imipenem non-susceptibility, cefepime MIC >8 µg/mL, and the peritoneal space as a culture site are independent clinical predictors of CPE among the Erta-NS-IAI Enterobacteriaceae isolates in the Asia-Pacific region.

Bactibilia in diseases of the biliary tract and pancreatic gland in patients older than 80 years: a STROBE-retrospective cohort study in a teaching hospital in Italy

Bile is a lipid-rich sterile solution produced in the liver that can be infected resulting in bactibilia. A higher incidence of postoperative infectious complications has been seen in patients with bactibilia. Recently, gram-negative bacteria have been linked to a tumor-associated inflammatory status. This study is a retrospective cohort study of 39 patients, who are over 80 years of age only (53.85% males and 46.15% females), hospitalized with diseases of the biliopancreatic system in one teaching hospital in Italy from January 2011 to December 2012 with a follow-up of 5 years. The most common biliary diseases after surgery were pancreatic head cancer (p < 0.0001) and gallbladder cancer (p = 0.0051), while the most common bacteria in the bile were E. coli (p = 0.0180) and Pseudomonas spp. (p < 0.0001). Uni- and multivariate linear correlation analysis revealed that patients with pancreatic head cancer had low survival times compared to patients with other diseases. Moreover, the bacterium type was a positive predictor of survival time compared to other variables. Our data confirm E. coli as a pathogen in patients with gallbladder and pancreatic cancer. Although the influence of bactibilia in developing surgical complications is limited, we consider that its composition is crucial to properly address the antibiotic treatment in biliary tract infections, especially in the elderly.

Tokyo Guidelines 2018: antimicrobial therapy for acute cholangitis and cholecystitis

Antimicrobial therapy is a mainstay of the management for patients with acute cholangitis and/or cholecystitis. The Tokyo Guidelines 2018 (TG18) provides recommendations for the appropriate use of antimicrobials for community-acquired and healthcare-associated infections. The listed agents are for empirical therapy provided before the infecting isolates are identified. Antimicrobial agents are listed by class-definitions and TG18 severity grade I, II, and III subcategorized by clinical settings. In the era of emerging and increasing antimicrobial resistance, monitoring and updating local antibiograms is underscored. Prudent antimicrobial usage and early de-escalation or termination of antimicrobial therapy are now important parts of decision-making. What is new in TG18 is that the duration of antimicrobial therapy for both acute cholangitis and cholecystitis is systematically reviewed. Prophylactic antimicrobial usage for elective endoscopic retrograde cholangiopancreatography is no longer recommended and the section was deleted in TG18. Free full articles and mobile app of TG18 are available at: http://www.jshbps.jp/modules/en/index.php?content_id=47. Related clinical questions and references are also included.

What Healthcare Workers Should Know about Environmental Bacterial Contamination in the Intensive Care Unit

Intensive care unit- (ICU-) acquired infections are a major health problem worldwide. Inanimate surfaces and equipment contamination may play a role in cross-transmission of pathogens and subsequent patient colonization or infection. Bacteria contaminate inanimate surfaces and equipment of the patient zone and healthcare area, generating a reservoir of potential pathogens, including multidrug resistant species. Traditional terminal cleaning methods have limitations. Indeed patients who receive a bed from prior patient carrying bacteria are exposed to an increased risk (odds ratio 2.13, 95% confidence intervals 1.62-2.81) of being colonized and potentially infected by the same bacterial species of the previous patient. Biofilm formation, even on dry surfaces, may play a role in reducing the efficacy of terminal cleaning procedures since it enables bacteria to survive in the environment for a long period and provides increased resistance to commonly used disinfectants. No-touch methods (e.g., UV-light, hydrogen peroxide vapour) are under investigation and further studies with patient-centred outcomes are needed, before considering them the standard of terminal cleaning in ICUs. Healthcare workers should be aware of the role of environmental contamination in the ICU and consider it in the broader perspective of infection control measures and stewardship initiatives.

Shifting trends in bacteriology and antimicrobial resistance among gastrointestinal fistula patients in China: an eight-year review in a tertiary-care hospital

Background

The purpose of this study was to determine the shifting trends in bacteriology and antimicrobial resistance of infectious specimens isolated from gastrointestinal (GI) fistula patients over eight years in China.

Methods

We retrospectively reviewed the microbial records of intra-abdominal specimens at a teaching hospital from 2008 to 2015. Study period was divided into the first half (2008–2011) and the second half (2012–2015). All isolates underwent antibiotic susceptibility testing by the micro dilution method.

Results

A total of 874 intra-abdominal isolates were consecutively collected from 502 GI fistula patients (mean age, 46.5 years, 71.1% male) during the study period. Patients in the second study period (2012–2015) were older (>65 years) and more likely to have experienced cancer. Over the entire study period, most infections were caused by E. coli (24.2%) and K. pneumonia (14.1%). There was a significant decrease in the proportion E. coli isolates that were extended- spectrum beta-lactamase (ESBL)-positive (P = 0.026). The proportion of E. coli resistant to imipenem increased from 14.3% in 2008–2011 to 25.9% in 2012–2015 (P = 0.037). Imipenem resistance prevalence was higher in ESBL-negative bacteria than ESBL-positive bacteria for both E. coli and K. pneumonia (P < 0.001). In Enterococcus, significant increase in resistance to ampicillin (P = 0.01) and moxifloxacin (P = 0.02) over time were observed. In Staphylococcus and fungi, rates of antibiotic resistance did not significantly change over the study period.

Conclusions

Gram-negative bacteria predominated as causative agents of intra-abdominal infections in GI fistula patients, and there was an increase in levels of resistance to certain antibiotics, particularly carbapenems. Infection control and source control are important tools available to surgeons to prevent the emergence of antibiotic-resistant pathogens.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2744-7) contains supplementary material, which is available to authorized users.

The role of Enterococcus spp. and multidrug-resistant bacteria causing pyogenic liver abscesses

Background

Pyogenic liver abscesses (PLA) remain a significant clinical problem. Unfortunately, little is known about current bacterial susceptibility profiles and the incidence of multidrug resistant organisms (MDROs) causing PLA in Western countries. Yet, this crucial information is pivotal to guide empirical antibiotic therapy. Aim of this study was to provide detailed characteristics of PLA with a special focus on underlying bacterial pathogens and their susceptibility to antibiotics.

Methods

A retrospective study of patients diagnosed with PLA from 2009 to 2015 in a large tertiary reference center in Germany was performed in order to characterize PLA and antimicrobial susceptibility profiles of causative bacterial species.

Results

Overall, 86 patients were included. The most common causes of PLA were bile duct stenosis/obstruction (31.4%) and leakage of biliary anastomosis (15.1%). Frequent predisposing diseases were malignancies (34.9%), diabetes (24.4%) and the presence of liver cirrhosis (16.3%). Of note, Enterococcus spp. were the most frequently cultured bacterial isolates (28.9%), and in 1/3 of cases vancomycin resistance was observed. In addition, a relevant frequency of gram-negative MDROs was identified. In particular, an alarming 10% and 20% of gram-negative bacteria were resistant to carbapenems and tigecycline, respectively. Of note, MDRO status did not predict ICU stay or survival in multivariate regression analysis. The mortality rate in our series was 16.3%.

Conclusion

Our study demonstrates an as yet underreported role of Enterococcus spp., often associated with vancomycin resistance, as well as of gram-negative MDROs causing PLA.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2543-1) contains supplementary material, which is available to authorized users.

Carbapenemases-producing Klebsiella pneumoniae in hospitals of two regions of Southern Italy

Carbapenem-resistant Klebsiella pneumoniae infections are reported with increasing frequency elsewhere in the world, representing a worrying phenomenon for global health. In Italy, there are hotspot data on the diffusion and type of carbapenemase-producing Enterobacteriaceae and K. pneumoniae in particular, with very few data coming from Apulia and Basilicata, two regions of Southern Italy. This study was aimed at characterizing by phenotypic and genotypic methods carbapenem-resistant K. pneumoniae isolated from several Hospitals of Apulia and Basilicata, Southern Italy. Antibiotic susceptibility was also evaluated. The relatedness of carbapenemase-producing K. pneumoniae strains was established by pulsed-field gel electrophoresis (PFGE). Among the 150 K. pneumoniae carbapenemase producers, KPC-3 genotype was the most predominant (95%), followed by VIM-1 (5%). No other genotypes were found and no co-presence of two carbapenemase genes was found. A full concordance between results obtained by both the phenotypic and the genotypic tests was observed. All strains were resistant to β-lactam antibiotics including carbapenems, and among antibiotics tested, only tetracycline and gentamycin showed low percentage of resistance (18% and 15%, respectively). Resistance to colistin was detected in 17.3% of strains studied. The analysis of PFGE profiles of the carbapenemases-positive strains shows that one group (B) of the five (A to E) main groups identified was the most prevalent and detected in almost all the hospitals considered, while the other groups were randomly distributed. Three different sequence types (ST 307, ST 258, and ST 512) were detected with the majority of isolates belonging to the ST 512. Our results demonstrated the wide diffusion of K. pneumoniae KPC-3 in the area considered, the good concordance between phenotypic and genotypic tests. Gentamicin and colistin had a good activity against these strains.

Critical issues for Klebsiella pneumoniae KPC-carbapenemase producing K. pneumoniae infections: a critical agenda

ABSTRACT 

The wide dissemination of carbapenemase producing K. pneumoniae (KPC-Kp) has caused a public health crisis of global dimensions, due to the serious infections in hospitalized patients associated with high mortality. In 2014, we aim to review clinical data on KPC-Kp at a time when a pro-active strategy (combating the problem before it is established) is no longer useful, focusing on epidemiology, patient risk profile, infection control, digestive tract colonization and treatment issues such as the role of carbapenems or carbapenem sparing strategies, colistin and resistance, dual carbapenem administration and the role of tigecycline. All these issues are illustrated prospectively to provide a forum for a Consensus strategy when not only intensive care units but also medical and surgical wards are affected by the epidemics.

Multi-drug-resistant Klebsiella pneumoniae pancreatitis: a new challenge in a serious surgical infection

BACKGROUND

Klebsiella pneumoniae is an important cause of nosocomial infections, but its role in severe acute pancreatitis (SAP) is not well defined. Few cases of K. pneumoniae associated SAP have been reported. Due to the emergence of extended-spectrum beta-lactamases (ESBLs) and carbapenemases, treatment of multidrug-resistant (MDR) K. pneumoniae presents a challenge. Tigecycline and colistin have gained recent attention for their broad-spectrum antimicrobial activity.

METHODS

We describe a case of SAP due to K. pneumoniae bearing K. pneumoniae carbapenemase (KPC) treated successfully with colistin plus tigecycline and offer a review of similar experiences published in the literature.

RESULTS

The case reported herein required surgical drainage of multiple pancreatic abscesses and treatment with tigecycline and colistin. Our comparative analysis revealed a number of unique features associated with SAP due to K. pneumoniae: 1) underlying pancreatic injury, 2) multiple drug resistance determinants and virulence factors that complicate treatment, and 3) surgical debridement as a requirement for cure.

CONCLUSION

As the prevalence of K. pneumoniae bearing KPC continues to increase in the healthcare setting, SAP caused by this MDR pathogen will become more common. Tigecycline plus colistin was a successful antibiotic regimen for the treatment of SAP due to K. pneumoniae bearing KPC.

Genomics of KPC-producing Klebsiella pneumoniae sequence type 512 clone highlights the role of RamR and ribosomal S10 protein mutations in conferring tigecycline resistance

Full genome sequences were determined for five Klebsiella pneumoniae strains belonging to the sequence type 512 (ST512) clone, producing KPC-3. Three strains were resistant to tigecycline, one showed an intermediate phenotype, and one was susceptible. Comparative analysis performed using the genome of the susceptible strain as a reference sequence identified genetic differences possibly associated with resistance to tigecycline. Results demonstrated that mutations in the ramR gene occurred in two of the three sequenced strains. Mutations in RamR were previously demonstrated to cause overexpression of the AcrAB-TolC efflux system and were implicated in tigecycline resistance in K. pneumoniae. The third strain showed a mutation located at the vertex of a very well conserved loop in the S10 ribosomal protein, which is located in close proximity to the tigecycline target site in the 30S ribosomal subunit. This mutation was previously shown to be associated with tetracycline resistance in Neisseria gonorrhoeae. A PCR-based approach was devised to amplify the potential resistance mechanisms identified by genomics and applied to two additional ST512 strains showing resistance to tigecycline, allowing us to identify mutations in the ramR gene.

Pancreatitis in tigecycline Phase 3 and 4 clinical studies

Objectives

To examine the incidence of pancreatitis among subjects enrolled in the tigecycline clinical trial programme, summarize cases and examine concomitant use of other pancreatitis-causing medications.

Methods

Subject data from Phase 3 and 4 comparative tigecycline studies were included in the analysis; investigator-reported adverse events of ‘pancreatitis’, ‘necrotizing pancreatitis’ or ‘pancreas disorder’ were reviewed. Data were summarized and cases were reported. No statistical comparisons were made. The incidence of overall pancreatitis with 95% CIs was calculated. The Wilson score method was used to calculate CIs.

Results

Nineteen subjects with investigator-determined pancreatitis were identified from the programme database, which included 3788 subjects treated with tigecycline and 3646 subjects treated with a comparator. There were 9 cases identified among the tigecycline-treated subjects [9 of 3788 (0.24%; 95% CI, 0.11–0.45)] and 10 cases among the comparator-treated subjects [10 of 3646 (0.27%; 95% CI, 0.13–0.50)]. The demographic characteristics of the subjects with pancreatitis were similar between treatment groups. The median duration of tigecycline therapy was 8.0 days compared with 11.0 days of comparator treatment. Concomitant or prior exposure to a Badalov class I medication was evident in the majority of subjects who developed pancreatitis. A numerically higher number of tigecycline-treated subjects were exposed to furosemide prior to the onset of pancreatitis than comparator-treated subjects.

Conclusions

Pancreatitis was uncommon in subjects treated with tigecycline, with an occurrence of <1%. Concomitant medications known to cause pancreatitis should be considered when prescribing tigecycline, but may not identify those at risk of developing pancreatitis.

Surgical pathology and the diagnosis of invasive visceral yeast infection: two case reports and literature review

Invasive mycoses are life-threatening opportunistic infections that have recently emerged as a cause of morbidity and mortality following general and gastrointestinal surgery.Candida species are the main fungal strains of gut flora. Gastrointestinal tract surgery might lead to mucosal disruption and cause Candida spp. to disseminate in the bloodstream.Here we report and discuss the peculiar clinical and morphological presentation of two cases of gastrointestinal Candida albicans lesions in patients who underwent abdominal surgery.Although in the majority of cases reported in the literature, diagnosis was made on the basis of microbiological criteria, we suggest that morphological features of fungi in histological sections of appropriate surgical specimens could help to detect the degree of yeast colonization and identify patients at risk of developing severe abdominal Candida infection.Better prevention and early antifungal treatments are highlighted, and relevant scientific literature is reviewed.

KPC - 3 Klebsiella pneumoniae ST258 clone infection in postoperative abdominal surgery patients in an intensive care setting: analysis of a case series of 30 patients

BACKGROUND

Abdominal surgery carries significant morbidity and mortality, which is in turn associated with an enormous use of healthcare resources. We describe the clinical course of 30 Intensive Care Unit (ICU) patients who underwent abdominal surgery and showed severe infections caused by Klebsiella pneumoniae sequence type (ST) 258 producing K. pneumoniae carbapenemase (KPC-Kp). The aim was to evaluate risk factors for mortality and the impact of a combination therapy of colistin plus recommended regimen or higher dosage of tigecycline.

METHODS

A prospective assessment of severe monomicrobial KPC-Kp infections occurring after open abdominal surgery carried out from August 2011 to August 2012 in the same hospital by different surgical teams is presented. Clinical and surgical characteristics, microbiological and surveillance data, factors associated with mortality and treatment regimens were analyzed. A combination regimen of colistin with tigecycline was used. A high dose of tigecycline was administered according to intra-abdominal abscess severity and MICs for tigecycline.

RESULTS

The mean age of the patients was 56.6 ± 15 and their APACHE score on admission averaged 22.72. Twenty out of 30 patients came from the surgical emergency unit. Fifteen patients showed intra-abdominal abscess, eight anastomotic leakage, four surgical site infection (SSI) and three peritonitis. The overall crude ICU mortality rate was 40% (12 out of 30 patients). Twelve of the 30 patients were started on a combination treatment of high-dose tigecycline and intravenous colistin. A significantly lower mortality rate was observed among those patients compared to patients treated with approved dose of tigecycline plus colistin. No adverse events were reported with high doses of tigecycline.

CONCLUSIONS

Critically-ill surgical patients are prone to severe post-surgical infectious complications caused by KPC-Kp. Timely microbiological diagnosis and optimizing antibiotic dosing regimens are essential to prevent worse outcomes. Further studies and well-controlled clinical trials are needed to define the optimal treatment of infections by KPC-Kp and, more generally, carbapenem-resistant bacteria.

Changing bacteriology of abdominal and surgical sepsis

PURPOSE OF REVIEW

This review focuses on recent changes in epidemiological aspects of bacteria-induced intra-abdominal infections (IAIs), including the dominant pathogens, antimicrobial susceptibility profiles, and emerging resistance phenotypes.

RECENT FINDINGS

Enterobacteriaceae species, including Escherichia coli and Klebsiella pneumoniae, remain the major pathogens contributing to abdominal sepsis, although Pseudomonas aeruginosa and Acinetobacter baumannii have recently become common causes of hospital-acquired IAIs. The prevalence of multidrug-resistant Gram-negative bacilli, especially those that produce extended-spectrum β-lactamases (ESBLs), has increased worldwide, although the distribution of those organisms varies from region to region. Furthermore, recent changes in interpretive breakpoints for antimicrobial susceptibility testing recommended by the Clinical Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST) have resulted in a marked increase in the reported rates of resistance among Gram-negative bacilli to carbapenems, extended-spectrum cephalosporins, and fluoroquinolones. Besides, routine detection and reporting of ESBL phenotypes for clinical isolates have not been recommended after following new interpretive breakpoints. More studies are needed to investigate the impacts of these changes on therapeutic strategies and epidemiological surveillance. In addition, pathogens carrying New Delhi metallo-β-lactamases (NDMs), K. pneumoniae carbapenemases (KPCs), and other carbapenemases show extended resistance to currently available antibiotics and rapid transfer between species and countries. Although some of these pathogens are still susceptible to tigecycline and colistin, rates of resistance to these two agents are rising.

SUMMARY

Abdominal sepsis due to multidrug-resistant bacteria, especially ESBL producers, and international and interspecies spreading of metallo-β-lactamase raise key therapeutic problems.

Rapid evolution and spread of carbapenemases among Enterobacteriaceae in Europe

Plasmid-acquired carbapenemases in Enterobacteriaceae, which were first discovered in Europe in the 1990s, are now increasingly being identified at an alarming rate. Although their hydrolysis spectrum may vary, they hydrolyse most β-lactams, including carbapenems. They are mostly of the KPC, VIM, NDM and OXA-48 types. Their prevalence in Europe as reported in 2011 varies significantly from high (Greece and Italy) to low (Nordic countries). The types of carbapenemase vary among countries, partially depending on the cultural/population exchange relationship between the European countries and the possible reservoirs of each carbapenemase. Carbapenemase producers are mainly identified among Klebsiella pneumoniae and Escherichia coli, and still mostly in hospital settings and rarely in the community. Although important nosocomial outbreaks with carbapenemase-producing Enterobacteriaceae have been extensively reported, many new cases are still related to importation from a foreign country. Rapid identification of colonized or infected patients and screening of carriers is possible, and will probably be effective for prevention of a scenario of endemicity, as now reported for extended-spectrum β-lactamase (mainly CTX-M) producers in all European countries.