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.

Klebsiella ozaenae in a Peritonsillar Abscess: A Case Report

A peritonsillar abscess (PTA) is an infection that primarily affects the peritonsillar space. The incidence is estimated to affect 30 per 100,000 individuals annually, with a higher prevalence between the 15- and 30-year-old age groups. The pathogenesis of a PTA is a crucial step in effective management and prevention. Typically, a PTA has a polymicrobial etiology, aerobic, and anaerobic bacteria of oral flora. Multiple papers in the literature have studied the incidence of Klebsiella species in PTA cases. However, few studies have isolated Klebsiella ozaenae in a PTA. We present a case of a 29-year-old patient who was admitted as a case of a PTA. He underwent an incision and drainage of the right PTA in the operation room. A significant amount of purulent fluid was drained with a positive culture of K. ozaenae.

Characteristics of Bacterial Biofilm Formation in Nasolacrimal Silicone Tubes Post-dacryocystorhinostomy

PURPOSE

To examine the biofilm formation characteristics of bacteria identified at the genus level in samples obtained from silicone tubes after dacryocystorhinostomy surgery.

METHODS

In the study involving consecutive patients who underwent dacryocystorhinostomy surgery at Ankara Bilkent City Hospital and whose silicone tubes were removed six months after surgery, between January 2023 and May 2023; the tubes were placed in glycerol-PBS (phosphate buffered saline) solution and cultured on descriptive selective media at the genus level. The biofilm-forming properties of the obtained isolates were examined in solid-air and liquid-air interphases. Salmonella Typhimurium ATCC SL1344 strain was used as the control bacterium.

RESULTS

As a result of the analysis of the samples taken from the patients, Pseudomonas spp. was identified in three of the samples, Staphylococcus spp. in five of the samples, and Streptococcus spp. in one of the samples. Among these samples, except for the bacteria identified in samples one and five, the rest were found to be strong biofilm producers. In all strong biofilm producers, the maximum biofilm production time was determined as 72 h and the incubation temperature was 37°C. The presence of cellulose and amyloid proteins in biofilm matrix structures is identified. Swimming and swarming motilities were observed in all bacterial samples.

CONCLUSION

Since biofilms are considered potential factors in the pathogenesis of infectious and inflammatory diseases, they are a subject that needs to be thoroughly investigated. In our study, although there were no clinical infections in any of the patients, biofilm formation was detected in the patient samples. The fact that the bacteria exhibited moderate to strong biofilm formation characteristics suggests that these microorganisms could be persistent infectious agents.

Uncommon Culprit, Familiar Foe: A Case of Septic Thrombophlebitis of the Internal Jugular Vein Triggered by Klebsiella Bacteremia

Septic thrombophlebitis of the internal jugular vein is characterized as Lemierre syndrome. Patients typically present with sore throat and fever and may present with a tender neck mass due to thrombophlebitis of the internal jugular vein. We present the case of a 57-year-old male with neck pain, fever, chills, and headaches who was diagnosed with internal jugular vein septic thrombophlebitis associated with catheter-related introduction of bacteria.

Extracorporeal Membrane Oxygenation (ECMO) in an Infant with COVID-19: A Case Report with Literature Review

BACKGROUND

SARS-CoV-2 infection tends to be lethal to the elderly population. However, sometimes children are also involved.

CASE PRESENTATION

We present the case of a female infant with a corrected gestational age of 39 weeks and 4 days with severe COVID-19 pneumonia and co-infection of Klebsiella pneumoniae that was supported with extracorporeal membrane oxygenation (ECMO).

RESULTS

We reported the clinical case and reviewed the literature articles on ECMO and Covid-19 in infants and children up to two years of age.

CONCLUSION

It is crucial to be aware of certain risk factors (severe prematurity, coinfection), which, when linked to SARS-CoV-2 infection, must immediately alert us to the possible criticality of the clinical condition of patients, as highlighted by our own clinical case.

Comparative Investigation into the Roles of Imipenem:Cyclodextrin Complexation and Antibiotic Combination in Combatting Antimicrobial Resistance in Gram-Negative Bacteria

Extensively drug-resistant (XDR), multidrug-resistant (MDR) and pandrug-resistant (PDR) Gram-negative microorganisms (GNBs) are considered a significant global threat. β-lactam and aminoglycoside combinations and imipenem:cyclodextrin inclusion complexes were studied for the treatment of lethal GNBs. This is because of the broad empiric coverage of the two drugs and their possession of different spectra of activity. Two cyclodextrins (β- and hydroxy propyl β-cyclodextrins) were utilized for inclusion complex formation with imipenem using the physical and kneading methods. In silico investigation using the molecular docking and Fourier-infrared spectroscopy (FTIR) were employed to estimate binding constant and confirm complex formation, respectively. The in vitro effects of amikacin and imipenem combination in comparison to the effect of imipenem-β- and hydroxy propyl β-cyclodextrin (CD) complexes against Klebsiella spp. and Acinetobacter baumannii were studied. The isolated microorganisms' antimicrobial responsiveness to various antibiotics (19 antibiotics) was evaluated. It was found that piperacillin/tazobactam and gentamycin (resistance rates were 33.3% and 34%, respectively) were the most effective antimicrobials. The in vitro studies have been performed by the checkerboard technique and time-killing assay. The studied combination of amikacin and imipenem showed a substantial drop in bacterial count (p < 0.05). The in vitro studies demonstrated a synergism for the investigated combination. Conventional PCR was used in molecular studies to identify the resistance genes bla IMP and aac (6')-Ib. The blaIMP and aac (6')-Ib were recorded in 38.2% and 3.6% of the studied isolates, respectively. The in vitro studies showed synergistic effects among the tested antibiotics with FICIs of ≤0.5. Finally, the study compared the reduction in bacterial count between the tested antibiotic combinations and imipenem:CD physical and kneaded mixtures. Imipenem:CD inclusion complexes demonstrated a significant bacterial count reduction over the antibiotic combination. These results highlight the emerging role of CDs as safe biofunctional excipients in the combat against superbug bacterial resistance.

Human Alcohol-Microbiota Mice have Increased Susceptibility to Bacterial Pneumonia

Preclinical studies have shown that chronic alcohol abuse leads to alterations in the gastrointestinal microbiota that are associated with behavior changes, physiological alterations, and immunological effects. However, such studies have been limited in their ability to evaluate the direct effects of alcohol-associated dysbiosis. To address this, we developed a humanized alcohol-microbiota mouse model to systematically evaluate the immunological effects of chronic alcohol abuse mediated by intestinal dysbiosis. Germ-free mice were colonized with human fecal microbiota from individuals with high and low Alcohol Use Disorders Identification Test (AUDIT) scores and bred to produce human alcohol-associated microbiota or human control-microbiota F1 progenies. F1 offspring colonized with fecal microbiota from individuals with high AUDIT scores had increased susceptibility to Klebsiella pneumoniae and Streptococcus pneumoniae pneumonia, as determined by increased mortality rates, pulmonary bacterial burden, and post-infection lung damage. These findings highlight the importance of considering both the direct effects of alcohol and alcohol-induced dysbiosis when investigating the mechanisms behind alcohol-related disorders and treatment strategies.

Ventilator-Associated Pneumonia in Paediatric Intensive Care Unit Patients: Microbiological Profile, Risk Factors, and Outcome

Introduction Ventilator-associated pneumonia (VAP) is one of the dreaded events in sick children who are ventilated in the paediatric intensive care unit (PICU) and has a high mortality rate. So, there is a need to know the causative organisms, risk factors, and possible predictors in a particular PICU for prevention, early identification, and treatment to decrease morbidity and mortality. This study was planned with the objectives to determine the microbiological profile, associated risk factors, and outcome of VAP in children. Methods In this observational cross-sectional study conducted at Dr. B C Roy Post Graduate Institute of Paediatric Science, Kolkata, India, 37 VAP cases were diagnosed using clinical pulmonary infection score >6 and confirmed by tracheal culture and X-ray. Results The number of paediatric patients suffering from VAP was 37 (36.2%). The commonest age group involvement was one to five years. The microbiological profile included Pseudomonas aeruginosa (29.8%) and Klebsiella pneumoniae (21.6%) as the commonest organisms followed by Staphylococcus aureus (18.9%) and Acinetobacter (13.5%). The factors significantly associated with the increased frequency of VAP were the use of steroids, sedation, and reintubation. The mean duration of mechanical ventilation (MV) in VAP was 15 days compared to non-VAP (seven days), and the longer duration of ventilation was significantly associated with VAP (p=0.00001). Mortality in VAP was 48.54% compared to non-VAP (55.84%) with no significant association (p=0.0843) of VAP with death occurrence. Conclusion The present study showed that VAP occurrence is associated with prolonged duration of MV, PICU stay, and hospital stay but is not significantly associated with mortality. It also indicated that gram-negative bacteria were the most common VAP causative organisms in this cohort.

Necrotizing Soft Tissue Infection of Left Shoulder and Upper Limb Following Intravenous Injection of Non-steroidal Anti-inflammatory Drug

Necrotizing soft tissue infection (NSTI) is a rapidly spreading and fulminant infection that may occur within any layer of skin and soft tissue and may result in sepsis and multiorgan failure. Cases of intravenous injection of drugs causing NSTIs have been reported, especially involving injection of illicit drugs or insulin. NSTI can be due to polymicrobial or monomicrobial infection and infection involving Klebsiella species has been rising, especially in patients with diabetes mellitus. This is a case of an extensive upper limb and shoulder Klebsiella pneumoniae NSTI following an injection of a non-steroidal anti-inflammatory drug in a diabetic patient. NSTI diagnosis is based on history and clinical examination, supplemented with imaging and laboratory investigations. Early recognition, extensive and serial debridement, antibiotics, and wound management are crucial for the better outcome of the disease. This patient underwent emergent debridement with antibiotics coverage, followed by serial debridement and wound care. The wound healed within the stipulated time, with good function of the affected limb following the rehabilitation program. 

Raoultella planticola Infection in Urine

Raoultella planticola is a gram-negative, aerobic, nonmotile bacteria that can be found in soil and water. This is a relatively rare organism with few case reports on it and only three reports of R. planticola-induced urinary tract infection (UTI) have been reported. Here we present a case of acute cystitis caused by R. planticola in a woman with atrial fibrillation and recurrent UTIs.

Genetic determinants facilitating the evolution of resistance to carbapenem antibiotics

In this era of rising antibiotic resistance, in contrast to our increasing understanding of mechanisms that cause resistance, our understanding of mechanisms that influence the propensity to evolve resistance remains limited. Here, we identified genetic factors that facilitate the evolution of resistance to carbapenems, the antibiotic of 'last resort', in Klebsiella pneumoniae, the major carbapenem-resistant species. In clinical isolates, we found that high-level transposon insertional mutagenesis plays an important role in contributing to high-level resistance frequencies in several major and emerging carbapenem-resistant lineages. A broader spectrum of resistance-conferring mutations for select carbapenems such as ertapenem also enables higher resistance frequencies and, importantly, creates stepping-stones to achieve high-level resistance to all carbapenems. These mutational mechanisms can contribute to the evolution of resistance, in conjunction with the loss of systems that restrict horizontal resistance gene uptake, such as the CRISPR-Cas system. Given the need for greater antibiotic stewardship, these findings argue that in addition to considering the current efficacy of an antibiotic for a clinical isolate in antibiotic selection, considerations of future efficacy are also important. The genetic background of a clinical isolate and the exact antibiotic identity can and should also be considered as they are determinants of a strain's propensity to become resistant. Together, these findings thus provide a molecular framework for understanding acquisition of carbapenem resistance in K. pneumoniae with important implications for diagnosing and treating this important class of pathogens.

Epidemiology of invasive bacterial infections in pneumococcal conjugate vaccine-vaccinated and -unvaccinated children under 5 years of age in Soweto, South Africa: a cohort study from a high-HIV burden setting

Background: There are limited data on paediatric invasive bacterial infections (IBI) and the impact of pneumococcal conjugate vaccine (PCV) on the spectrum of IBI pathogens, specifically in African countries with a high prevalence of HIV infection.Aim: To describe the epidemiology of IBI in a cohort of children <5 years of age in Soweto, South Africa.Methods: A cohort of children enrolled into a PCV9 efficacy trial conducted from 1998 until 2005 was used for secondary data analysis. Surveillance data were collected from admission wards at Chris Hani Baragwanath Academic Hospital. The incidence of IBI was calculated using person-time, stratified by age group, gender, PCV9 vaccination status and HIV infection status. Risk factors for IBI were investigated using binomial logistic regression.Results: A total of 395 cases of laboratory-confirmed IBI were identified. HIV infection and not receiving PCV9 vaccination were risk factors for IBI hospitalisation. PCV9 vaccination was associated with reductions in IBI hospitalisation (IRR 0.76, p = 0.006) solely owing to reductions in the incidence of Streptococcus pneumoniae (IRR 0.56, p < 0.001). PCV9 vaccination had no effect on the incidence of Haemophilus influenza type b or Salmonella species IBI. There was an increase in Klebsiella species IBI (IRR 3.50, p = 0.019) and a trend towards a higher incidence of Staphylococcus aureus IBI (IRR 1.90, p = 0.099) in PCV9-vaccinated children.Conclusions: PCV9 vaccination was effective in reducing the incidence of IBI hospitalisation in children through reductions in the incidence of S. pneumoniae. The results show that trends in other IBI causative pathogens (specifically S. aureus and Klebsiella species) should be monitored in the era of PCV vaccination.Abbreviations: ART, antiretroviral therapy; CI, confidence interval; Hib, Haemophilus influenza type b; HIV, human immunodeficiency virus; HIV+PCV-, HIV-infected, placebo-vaccinated group; HIV+PCV+, HIV-infected, PCV9-vaccinated group; HIV-PCV-, HIV-uninfected, placebo-vaccinated group; HIV+PCV+, HIV-infected, PCV9-vaccinated group; IBI, invasive bacterial infection; IPD, invasive pneumococcal disease; IRR, incidence rate ratio; IQR, interquartile range; OR, odds ratio; PCV, pneumococcal conjugate vaccine; PCV7, 7-valent pneumococcal conjugate vaccine; PCV9, 9-valent pneumococcal conjugate vaccine; PY, person-years; RCT, randomised control trial.

In vitro study of antimicrobial activity on Klebsiella Pneumoniae biofilms in endotracheal tubes

Effective treatment approaches for biofilms in endotracheal tubes (ETTs) are lacking. In this study, we evaluated the in vitro effects of five antimicrobials against biofilms formed by Klebsiella pneumoniae in ETTs. K. pneumoniae was added to minimal mucin medium prior to inoculation in microtiter plates containing ETT fragments. Biofilm susceptibility was assessed by crystal violet staining. At 24 h, the antimicrobials significantly reduced biofilm formation. At 48 h, all of the antimicrobial agents exhibited significant reductions in biofilm formation, even at concentrations above the minimum inhibitory concentration (MIC). Tigecycline and fosfomycin showed the greatest inhibition capacity, with good activity at concentrations twofold greater than the MIC. K. pneumoniae exhibited excellent biofilm formation ability, with formation in the first 24 h and significantly reduced antimicrobial activity. These results contribute to the establishment of new antibiotic breakpoints for the adequate management of infections associated with biofilm formation. Abbreviations ETT Endotracheal tube MIC Minimum inhibitory concentration MBIC Minimum biofilm inhibitory concentration OD Optical density PBS Phosphate-buffered saline VAP Ventilator-associated pneumonia.

Molecular Detection of TEM, SHV and CTX-M Genes Among Gram-negative Klebsiella Isolates

INTRODUCTION

In the past few years, the use of antimicrobial drugs against a wide range of pathogens has increased significantly. This extensive use of drugs has increased the resistance rate in microbial community widely. Molecular techniques for the detection of resistance are more reliable as compared to the conventional phenotypic method.

BACKGROUND

The family Enterobacteriaceae is considered to be an important cause of nosocomial infections due to its predominantly active species such as E. coli, Klebsiella and Pseudomonas. These organisms are mainly involved in causing pneumonia, sepsis, post-surgical and urinary tract infections. Resistance against antimicrobial drugs among these isolates is increasing more rapidly all over the world. This study primarily focuses on the resistant isolates of Klebsiella species. The drug resistance in Klebsiella isolates is found to be associated with the production of resistance enzymes such as beta lactamase and extended spectrum beta lactamase (ESBLs) which confer resistance, most specifically against cephalosporins and extended spectrum cephalosporins. Since these enzymes are plasmid mediated, they can also produce resistance against several other antimicrobials. It has been found that among the genus Klebsiella, ESBLs are more prevalent in K. pneumoniae followed by K. oxytoca.

METHODS

In this study, we estimated the distribution of ESBL producers among Klebsiella species and performed their genetic characterization. A total of 236 gram-negative isolates were collected from different microbiological laboratories, during the period January 2010 till January 2012. Among these gram-negative isolates, 125 were identified as Klebsiella species. After species identification, Kirby Bauer disk diffusion method was used for antimicrobial susceptibility profiling. Furthermore, the phenotypic detection of ESBL producers was performed by double disc synergy and combination disc methods. Resistance genes responsible for the production of beta lactamase and extended spectrum beta lactamase enzymes were detected by Polymerase chain reaction. DNA sequencing was performed by selecting an ESBL producing Klebsiella pneumoniae strain with a positive blaTEM gene.

RESULTS

In this study, we found 48%, 43.2% and 2.4% of SHV, TEM, and CTX-M resistance genes respectively in Klebsiella isolates. The DNA sequence ESBL and blaTEM positive Klebsiella strain showed 94% similarity with Klebsiella pneumoniae KUN5033 blaTEM gene for class A beta-lactamase TEM-198 analyzed by the Basic Local Alignment Search Tool (BLAST).

CONCLUSION

Since there is an intense need of research in the field of drug resistance for implementing strict antibiotic control policies in hospitals, health care centers, laboratories, etc., the present study is dedicatedly conducted to estimate the drug resistant Klebsiella isolates, specifically the Beta lactamase and Extended Spectrum Beta Lactamase producers, at molecular level.

An unusual case of noma caused by Klebsiella pnuemoniae and its management

Noma or cancrum oris is an orofacial gangrene causing progressive mutilating destruction of the infected tissues. It mainly affects malnourished children with poor oral hygiene and concurrent debilitating systemic illnesses. It is a polymicrobial infection and borrelia vincentii and fusobacterium are the most important pathogens known. We present a case of a boy aged 2.5 years with noma where klebsiella was grown and was the initial cause of failure of empiric therapy.

Disturbances of the Perioperative Microbiome Across Multiple Body Sites in Patients Undergoing Pancreaticoduodenectomy

OBJECTIVE

The goals of this study were to characterize bacterial communities within fecal samples, pancreatic fluid, bile, and jejunal contents from patients undergoing pancreaticoduodenectomy (PD) and to identify associations between microbiome profiles and clinical variables.

METHODS

Fluid was collected from the pancreas, common bile duct, and proximal jejunum from 50 PD patients. Postoperative fecal samples were also collected. The microbial burden within samples was quantified with droplet digital polymerase chain reaction. Bacterial 16S ribosomal RNA gene sequences were amplified, sequenced, and analyzed. Data from fecal samples were compared with publicly available data obtained from volunteers.

RESULTS

Droplet digital polymerase chain reaction confirmed the presence of bacteria in all sample types, including pancreatic fluid. Relative to samples from the American Gut Project, fecal samples from PD patients were enriched with Klebsiella and Bacteroides and were depleted of anaerobic taxa (eg, Roseburia and Faecalibacterium). Similar patterns were observed within PD pancreas, bile, and jejunal samples. Postoperative fecal samples from patients with a pancreatic fistula contained increased abundance of Klebsiella and decreased abundance of commensal anaerobes, for example, Ruminococcus.

CONCLUSIONS

This study confirms the presence of altered bacterial populations within samples from PD patients. Future research must validate these findings and may evaluate targeted microbiome modifications to improve outcomes in PD patients.

Trilogy of sequential infections in a diabetic male

Uncontrolled diabetes is a known immunosuppressive state. It predisposes individuals to bacterial and fungal infections. The present case report demonstrates sequential infections by Klebsiella followed by tuberculosis and later development of mucormycosis in a poorly controlled diabetic patient. Timing of diagnosis is of essence because of high mortality seen with such pulmonary infections. High index of suspicion needs to be maintained as the same individual may harbor multiple infections as highlighted in this case.

Community-acquired Klebsiella pneumoniae bacteremia: global differences in clinical patterns

We initiated a worldwide collaborative study, including 455 episodes of bacteremia, to elucidate the clinical patterns of Klebsiella pneumoniae. Historically, community-acquired pneumonia has been consistently associated with K. pneumoniae. Only four cases of community-acquired bacteremic K. pneumoniae pneumonia were seen in the 2-year study period in the United States, Argentina, Europe, or Australia; none were in alcoholics. In contrast, 53 cases of bacteremic K. pneumoniae pneumonia were observed in South Africa and Taiwan, where an association with alcoholism persisted (p=0.007). Twenty-five cases of a distinctive syndrome consisting of K. pneumoniae bacteremia in conjunction with community-acquired liver abscess, meningitis, or endophthalmitis were observed. A distinctive form of K. pneumoniae infection, often causing liver abscess, was identified, almost exclusively in Taiwan.

Gram-negative bacterial pneumonia with secondary aspergillosis in an AIDS patient

A 40-year-old, HIV-infected female patient received antibiotic treatment for a urinary tract infection. After the initial success of therapy and a symptom-free period, she developed pneumonia with septic shock and adult respiratory distress syndrome (ARDS). In spite of intensive care and respirator therapy with positive end-expiratory pressure (PEEP), she died of infectious toxic shock. Autopsy findings showed relapsing, gram-negative, bacterial pneumonia (morphologically compatible with Klebsiella pneumonia) and secondary, invasive aspergillosis. The pathogenesis and epidemiology of these unusual complications of AIDS are discussed.