Bacteremia due to ESKAPE pathogens: An emerging problem in cancer patients

Dissecting bloodstream infections in febrile neutropenic patients with hematological malignancies, a decade-long single center retrospective observational study (2009-2019)

BACKGROUND

The use of ill-suited antibiotics is a significant risk factor behind the increase in the mortality, morbidity, and economic burden for patients who are under treatment for hematological malignancy (HM) and bloodstream infections (BSI). Such unfitting treatment choices intensify the evolution of resistant variants which is a public health concern due to possible healthcare-associated infection spread to the general population. Hence, this study aims to evaluate antibiograms of patients with BSI and risk factors associated with septicemia.

METHODS

A total of 1166 febrile neutropenia episodes (FNE) among 513 patients with HM from the National Center for Cancer Care and Research (NCCCR), Qatar, during 2009-2019 were used for this study. The socio-demographic, clinical, microbial, and anti-microbial data retrieved from the patient's health records were used.

RESULTS

We analyzed the sensitivity of gram-negative and gram-positive bacilli reported in HM-FN-BSI patients. Out of the total 512 microorganisms isolated, 416 (81%) were gram-negative bacteria (GNB), 76 (15%) were gram-positive bacteria (GPB) and 20 (4%) were fungi. Furthermore, in 416 GNB, 298 (71.6%) were Enterobacteriaceae sp. among which 121 (41%) were ESBL (Extended Spectrum Beta-Lactamase) resistant to Cephalosporine third generation and Piperacillin-Tazobactam, 54 (18%) were Carbapenem-resistant or multidrug-resistant organism (MDRO). It's noteworthy that the predominant infectious agents in our hospital include E. coli, Klebsiella species, and P. aeruginosa. Throughout the study period, the mortality rate due to BSI was 23%. Risk factors that show a significant correlation with death are age, disease status, mono or polymicrobial BSI and septic shock.

CONCLUSION

Decision pertaining to the usage of antimicrobials for HM-FN-BSI patients is a critical task that relies on the latest pattern of prevalence, treatment resistance, and clinical outcomes. Analysis of the antibiogram of HM-FN-BSI patients in Qatar calls for a reconsideration of currently followed empirical antibiotic therapy towards better infection control and antimicrobial stewardship.

Short Antimicrobial Peptide Derived from the Venom Gland Transcriptome of Pamphobeteus verdolaga Increases Gentamicin Susceptibility of Multidrug-Resistant Klebsiella pneumoniae

Infectious diseases account for nine percent of annual human deaths, and the widespread emergence of antimicrobial resistances threatens to significantly increase this number in the coming decades. The prospect of antimicrobial peptides (AMPs) derived from venomous animals presents an interesting alternative for developing novel active pharmaceutical ingredients (APIs). Small, cationic and amphiphilic peptides were predicted from the venom gland transcriptome of Pamphobeteus verdolaga using a custom database of the arthropod's AMPs. Ninety-four candidates were chemically synthesized and screened against ATCC® strains of Escherichia coli and Staphylococcus aureus. Among them, one AMP, named PvAMP66, showed broad-spectrum antimicrobial properties with selectivity towards Gram-negative bacteria. It also exhibited activity against Pseudomonas aeruginosa, as well as both an ATCC® and a clinically isolated multidrug-resistant (MDR) strain of K. pneumoniae. The scanning electron microscopy analysis revealed that PvAMP66 induced morphological changes of the MDR K. pneumoniae strain suggesting a potential "carpet model" mechanism of action. The isobologram analysis showed an additive interaction between PvAMP66 and gentamicin in inhibiting the growth of MDR K. pneumoniae, leading to a ten-fold reduction in gentamicin's effective concentration. A cytotoxicity against erythrocytes or peripheral blood mononuclear cells was observed at concentrations three to thirteen-fold higher than those exhibited against the evaluated bacterial strains. This evidence suggests that PvAMP66 can serve as a template for the development of AMPs with enhanced activity and deserves further pre-clinical studies as an API in combination therapy.

Prevalence of blood stream infections and associated factors among febrile neutropenic cancer patients on chemotherapy at Ocean Road Cancer Institute, Tanzania

BACKGROUND

Febrile Neutropenia (FN) caused by bacteria in cancer patients is associated with poor prognosis. The aim of this study was to determine the prevalence of FN and associated factors among cancer patients on chemotherapy at Ocean Road Cancer Institute (ORCI), Tanzania.

METHODS

A cross-sectional study was conducted from June to September 2019. Study participants were conveniently recruited. A desk review of participants medical records was performed. Standard microbiological procedures used to culture and identify the bacterial isolates from the positive blood cultures of participants that presented with FN. Kirby-Bauer disc diffusion was used to perform the antibiotics susceptibility testing. SPSS version 20.0 and MS Excel were used in data entry and analysis. Chi-Square was used as a measure of association between various factors and neutropenia. P-value less than 0.05 was considered statistically significant.

RESULTS

A total 213 participants were enrolled. Of these 76.1% were female. Most of the participants came from the Coast region. Majority of participants presented with breast Cancer (36.2%) and GIT (20.2%). The prevalence of FN and bacteremia was 5.6% and 35.3% respectively. Staphylococcus Aureus (60%) and Coagulase-Negative Staphylococci (40%) were the main isolates. Of the 6 isolates tested most were resistant to Co-Trimoxazole 4/6 (66.7%) and Doxycycline 3/6 (50%). FN was positively associated with chemotherapy regimen (P = 0.0001), platelets count (P = 0.0001) and use of G-CSF (P = 0.0001).

CONCLUSION

The prevalence of FN among the cancer patients on chemotherapy in Tanzania is low but associated with drug-resistant bacteria.

Multi-drug resistant ESKAPE pathogens and the uses of plants as their antimicrobial agents

Infections by ESKAPE (Enterococcus sp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pathogens cause major concern due to their multi-drug resistance (MDR). The ESKAPE pathogens are frequently linked to greater mortality, diseases, and economic burden in healthcare worldwide. Therefore, the use of plants as a natural source of antimicrobial agents provide a solution as they are easily available and safe to use. These natural drugs can also be enhanced by incorporating silver nanoparticles and combining them with existing antibiotics. By focussing the attention on the ESKAPE organisms, the MDR issue can be addressed much better.

Bacterial Infections and Cancer: Exploring This Association And Its Implications for Cancer Patients

Bacterial infections are common in the etiology of human diseases owing to the ubiquity of bacteria. Such infections promote the development of periodontal disease, bacterial pneumonia, typhoid, acute gastroenteritis, and diarrhea in susceptible hosts. These diseases may be resolved using antibiotics/antimicrobial therapy in some hosts. However, other hosts may be unable to eliminate the bacteria, allowing them to persist for long durations and significantly increasing the carrier's risk of developing cancer over time. Indeed, infectious pathogens are modifiable cancer risk factors, and through this comprehensive review, we highlight the complex relationship between bacterial infections and the development of several cancer types. For this review, searches were performed on the PubMed, Embase, and Web of Science databases encompassing the entirety of 2022. Based on our investigation, we found several critical associations, of which some are causative: Porphyromonas gingivalis and Fusobacterium nucleatum are associated with periodontal disease, Salmonella spp., Clostridium perfringens, Escherichia coli, Campylobacter spp., and Shigella are associated with gastroenteritis. Helicobacter pylori infection is implicated in the etiology of gastric cancer, and persistent Chlamydia infections present a risk factor for the development of cervical carcinoma, especially in patients with the human papillomavirus (HPV) coinfection. Salmonella typhi infections are linked with gallbladder cancer, and Chlamydia pneumoniae infection is implicated in lung cancer, etc. This knowledge helps identify the adaptation strategies used by bacteria to evade antibiotic/antimicrobial therapy. The article also sheds light on the role of antibiotics in cancer treatment, the consequences of their use, and strategies for limiting antibiotic resistance. Finally, the dual role of bacteria in cancer development as well as in cancer therapy is briefly discussed, as this is an area that may help to facilitate the development of novel microbe-based therapeutics as a means of securing improved outcomes.

Multidrug-Resistant Acinetobacter baumannii Infections in the United Kingdom versus Egypt: Trends and Potential Natural Products Solutions

Acinetobacter baumannii is a problematic pathogen of global concern. It causes multiple types of infection, especially among immunocompromised individuals in intensive care units. One of the most serious concerns related to this pathogen is its ability to become resistant to almost all the available antibiotics used in clinical practice. Moreover, it has a great tendency to spread this resistance at a very high rate, crossing borders and affecting healthcare settings across multiple economic levels. In this review, we trace back the reported incidences in the PubMed and the Web of Science databases of A. baumannii infections in both the United Kingdom and Egypt as two representative examples for countries of two different economic levels: high and low-middle income countries. Additionally, we compare the efforts made by researchers from both countries to find solutions to the lack of available treatments by looking into natural products reservoirs. A total of 113 studies reporting infection incidence were included, with most of them being conducted in Egypt, especially the recent ones. On the one hand, this pathogen was detected in the UK many years before it was reported in Egypt; on the other hand, the contribution of Egyptian researchers to identifying a solution using natural products is more notable than that of researchers in the UK. Tracing the prevalence of A. baumannii infections over the years showed that the infections are on the rise, especially in Egypt vs. the UK. Further concerns are linked to the spread of antibiotic resistance among the isolates collected from Egypt reaching very alarming levels. Studies conducted in the UK showed earlier inclusion of high-throughput technologies in the tracking and detection of A. baumannii and its resistance than those conducted in Egypt. Possible explanations for these variations are analyzed and discussed.

Rational Discovery of Antimicrobial Peptides by Means of Artificial Intelligence

Antibiotic resistance is a worldwide public health problem due to the costs and mortality rates it generates. However, the large pharmaceutical industries have stopped searching for new antibiotics because of their low profitability, given the rapid replacement rates imposed by the increasingly observed resistance acquired by microorganisms. Alternatively, antimicrobial peptides (AMPs) have emerged as potent molecules with a much lower rate of resistance generation. The discovery of these peptides is carried out through extensive in vitro screenings of either rational or non-rational libraries. These processes are tedious and expensive and generate only a few AMP candidates, most of which fail to show the required activity and physicochemical properties for practical applications. This work proposes implementing an artificial intelligence algorithm to reduce the required experimentation and increase the efficiency of high-activity AMP discovery. Our deep learning (DL) model, called AMPs-Net, outperforms the state-of-the-art method by 8.8% in average precision. Furthermore, it is highly accurate to predict the antibacterial and antiviral capacity of a large number of AMPs. Our search led to identifying two unreported antimicrobial motifs and two novel antimicrobial peptides related to them. Moreover, by coupling DL with molecular dynamics (MD) simulations, we were able to find a multifunctional peptide with promising therapeutic effects. Our work validates our previously proposed pipeline for a more efficient rational discovery of novel AMPs.

Design, Screening, and Testing of Non-Rational Peptide Libraries with Antimicrobial Activity: In Silico and Experimental Approaches

One of the challenges of modern biotechnology is to find new routes to mitigate the resistance to conventional antibiotics. Antimicrobial peptides (AMPs) are an alternative type of biomolecules, naturally present in a wide variety of organisms, with the capacity to overcome the current microorganism resistance threat. Here, we reviewed our recent efforts to develop a new library of non-rationally produced AMPs that relies on bacterial genome inherent diversity and compared it with rationally designed libraries. Our approach is based on a four-stage workflow process that incorporates the interplay of recent developments in four major emerging technologies: artificial intelligence, molecular dynamics, surface-display in microorganisms, and microfluidics. Implementing this framework is challenging because to obtain reliable results, the in silico algorithms to search for candidate AMPs need to overcome issues of the state-of-the-art approaches that limit the possibilities for multi-space data distribution analyses in extremely large databases. We expect to tackle this challenge by using a recently developed classification algorithm based on deep learning models that rely on convolutional layers and gated recurrent units. This will be complemented by carefully tailored molecular dynamics simulations to elucidate specific interactions with lipid bilayers. Candidate AMPs will be recombinantly-expressed on the surface of microorganisms for further screening via different droplet-based microfluidic-based strategies to identify AMPs with the desired lytic abilities. We believe that the proposed approach opens opportunities for searching and screening bioactive peptides for other applications.

Klebsiella pneumoniae: Prevalence, Reservoirs, Antimicrobial Resistance, Pathogenicity, and Infection: A Hitherto Unrecognized Zoonotic Bacterium

Klebsiella pneumoniae is considered an opportunistic pathogen, constituting an ongoing health concern for immunocompromised patients, the elderly, and neonates. Reports on the isolation of K. pneumoniae from other sources are increasing, many of which express multidrug-resistant (MDR) phenotypes. Three phylogroups were identified based on nucleotide differences. Niche environments, including plants, animals, and humans appear to be colonized by different phylogroups, among which KpI (K. pneumoniae) is commonly associated with human infection. Infections with K. pneumoniae can be transmitted through contaminated food or water and can be associated with community-acquired infections or between persons and animals involved in hospital-acquired infections. Increasing reports are describing detections along the food chain, suggesting the possibility exists that this could be a hitherto unexplored reservoir for this opportunistic bacterial pathogen. Expression of MDR phenotypes elaborated by these bacteria is due to the nature of various plasmids carrying antimicrobial resistance (AMR)-encoding genes, and is a challenge to animal, environmental, and human health alike. Raman spectroscopy has the potential to provide for the rapid identification and screening of antimicrobial susceptibility of Klebsiella isolates. Moreover, hypervirulent isolates linked with extraintestinal infections express phenotypes that may support their niche adaptation. In this review, the prevalence, reservoirs, AMR, Raman spectroscopy detection, and pathogenicity of K. pneumoniae are summarized and various extraintestinal infection pathways are further narrated to extend our understanding of its adaptation and survival ability in reservoirs, and associated disease risks.

A clinical approach to non-neutropenic fever in children with cancer

BACKGROUND

There are a limited number of studies that address non-neutropenic fever episodes in children with cancer, and no standard approach exists.

METHOD

We opt to retrospectively analyze the efficacy of the current clinical approach for management of non-neutropenic fever episodes and the associated risk factors among children with cancer at the Princess Noorah Oncology Center from May 2016 through December 2017.

RESULTS

A total of 480 non-neutropenic fever episodes were identified in 131 children, of which 62 episodes were triaged as high-risk non-neutropenic fever and 418 as low-risk non-neutropenic fever. Of those 480 non-neutropenic fever, 361 episodes (75.2%) were associated with the presence of central venous catheters. The overall failure rate of ceftriaxone mono-therapy was observed in 75.6% (11.7% in high-risk non-neutropenic fever with a mean C-reactive protein level of 21.1 (±23.2) mmol/L and 63.9% in low-risk non-neutropenic fever with a mean C-reactive protein level of 17.6 (±53.9) mmol/L). The overall bacteremia rate was 14.4%. The type of organisms isolated was mainly high-risk organisms in 59 non-neutropenic fever episodes (85.5%), OR 1.78 (95% CI: 0.45-7.04) p = 0.41. Of note, all bacteremia were associated with the presence of central venous catheter (100%). Of all the examined risk factors of outpatient treatment failure in low-risk non-neutropenic fever, only prolonged fever of more than three days were significantly associated with bacteremia OR 8.107 [95% CI: 1.744-37.691], p = 0.008. Noteworthy is that almost 43% of non-neutropenic fever episodes were associated with respiratory symptoms. This study provides a baseline for future prospective research assessing the pattern of non-neutropenic fever by focusing on associated risk factors.

Molecular characterisation of an Acinetobacter baumannii outbreak

Background

Acinetobacter baumannii are problematic hospital pathogens, and the increased incidence of multi drug resistance has significantly limited treatment options. The global epidemiology is not fully characterised due to large data gaps from low- and middle-income countries. This study characterised the molecular epidemiology of an A. baumanniii outbreak in Egypt.

Methods

Fifty-four A. baumannii isolates were recovered from a 4-month-outbreak at Tanta University Hospitals (TUH). Associated clinical and demographic data, and the antibiograms were analysed, and Carbapenem resistant isolates were screened for acquired carbapenemase genes by PCR and sequencing. Epidemiological typing was performed by single-locus sequencing of bla_OXA-51-like and Multi Locus Sequence Typing (MLST), and sequence types (STs) were analysed based on maximum-likelihood phylogeny (PhyML) to identify relatedness.

Findings

Immune suppression and ICU admission were the most common co-morbidity and risk factor. Carbapenem resistance accounted for 81%, and correlated with the presence of OXA-23, NDM-1 and -2, and VIM-1 and -2 carbapenemases. Nine different bla_OXA-51-like genes were identified which corresponded to 22 different Sequence Types (STs), including 10 novel. International clone (IC2) was the predominant clone. PhyML analysis revealed the presence of 2 distinct clones with multiple sub-lineages.

Conclusion

Given the short duration of the study, there was a rare heterogeneous population in the hospital. Carbapenem resistance is mediated by acquired carbapenemases in diverse lineages indicating the possibility of horizontal gene transfer. The diversity indicates the influx of multiple lineages of IC2 into TUH from unknown sources. Molecular epidemiological studies are essential for infection prevention and control measures.

Healthcare-Associated Infections Due to Multidrug-Resistant Organisms: a Surveillance Study on Extra Hospital Stay and Direct Costs

BACKGROUND

The increasing antimicrobial resistance poses a challenge to surveillance systems and raises concerns about the impact of multidrug-resistant organisms on patient safety.

OBJECTIVE

The study aimed to estimate extra hospital stay and economic burden of infections due to alert organisms - mostly multidrug-resistant - in a teaching hospital.

METHODS

The present retrospective matched cohort study was conducted based on the analysis of hospital admissions at Sant'Andrea Teaching Hospital in Rome from April to December 2015. Extra hospital stay was the difference in the length of stay between each case and control. All the patients developing an infection due to an alert organism were considered cases, all others were eligible as controls. The costs of LOS were evaluated by multiplying the extra stay with the hospital daily cost.

RESULTS

Overall, 122 patients developed an infection due to alert organisms and were all matched with controls. The attributable extra stay was of 2,291 days (mean 18.8; median 19.0) with a significantly increased hospitalization in intensive care units (21.2 days), bloodstream infections (52.5 days), and infections due to Gram-negative bacteria (mean 29.2 days; median 32.6 days). Applying the single day hospital cost, the overall additional expenditure was 11,549 euro per patient. The average additional cost of antibiotic drugs for the treatment of infections was about 1,200 euro per patient.

CONCLUSION

The present study presents an accurate mapping of the clinical and economic impact of infections attributable to alert organisms demonstrating that infections due to multidrug-resistant organisms are associated with higher mortality, longer hospital stays, and increased costs. Article Highlights Box: The increasing antimicrobial resistance poses a challenge for surveillance systems and raises concerns about the impact of multidrug-resistant organisms on patient safety. • Healthcare-associated infections (HAIs) have historically been recognized as a significant public health problem requiring close surveillance. • Despite several and reliable findings have been achieved on clinical issues, our knowledge on the economic impact of healthcare-associated infections due to multidrug-resistant organisms needs to be widened. • Estimating the cost of infections due to multidrug-resistant organisms in terms of extra hospital stay and economic burden is complex, and the financial impact varies across different health systems. • Evaluations of social and economic implications of hospital infections play an increasingly important role in the implementation of surveillance systems. • The costs of infection prevention and control programs and dedicated personnel are relatively low and self-sustainable when efficient.

Multiple sequence types responsible for healthcare-associated Acinetobacter baumannii dissemination in a single centre in Egypt

Background

Acinetobacter baumannii is an increasingly worrying organism in the healthcare setting, due to its multidrug resistance and persistence. Prolonged hospitalisation, immunocompromised patients and excessive antibiotic exposure all contribute to increasing the risk of A. baumannii infections, which makes cancer patients a significant risk group. This study aims to investigate the dissemination of A. baumannii at the National Cancer Institute (NCI) in Cairo – Egypt.

Methods

All bacterial isolates were typed using Multi-locus Sequence Typing (MLST) to characterise the epidemiology of isolates. The intrinsic OXA-51-like, and the acquired carbapanemases OXA-23, − 24/40, − 58, NDM, IMP, and VIM were also amplified and sequenced to genetically identify mechanisms of carbapenem resistance.

Results

MLST results show a high degree of multi-clonal dissemination, with 18 different Sequence Types (STs) identified, including 5 novel. The majority of isolates belonged to International Clone (IC) 2, and carbapenem resistance was detected in 93% of isolates and mediated by bla_OXA-23, bla_OXA-58, bla_NDM-1 and bla_VIM-1. We also report the presence of a resistant ST732 (OXA-378) which has been previously identified in migratory birds_.

Conclusions

Multiple highly resistant clones were identified in a Cancer hospital in Cairo. It is vital that clinicians and healthcare workers are aware of the population of A. baumannii present in order to have appropriate treatment and infection control practices.

Tracing the dissemination of the international clones of multidrug-resistant Acinetobacter baumannii among cancer patients in Egypt using the PCR-based open reading frame typing (POT) method

OBJECTIVES

The aim of this study was to perform an epidemiological surveillance of multidrug-resistant (MDR) Acinetobacter baumannii genetic lineages among cancer patients in Egypt using the PCR-based open reading frame typing (POT) method.

METHODS

A total of 160 MDR A. baumannii isolates were collected between January 2015 and December 2017 at a tertiary-care centre in Egypt. VITEK®2 system was used for preliminary species identification and antimicrobial susceptibility testing. The POT method was applied for confirmation of species identification and molecular epidemiological typing of the isolates.

RESULTS

MDR A. baumannii isolates were classified into 15 POT types, including POT 122 (n=69), POT 69 (n=22) and other miscellaneous POT types (MPOTs) including POT 0, 8, 10, 12, 14, 40, 44, 52, 56, 93, 104, 106 and 108 (n=69). POT 122 isolates infected or colonised 61% of patients hospitalised in surgical wards and 54% of patients diagnosed with solid tumours and 51% were adults; whereas MPOT isolates infected or colonised 51% of patients hospitalised in paediatric wards and 49% of patients diagnosed with haematological malignancies and 51% were paediatric patients (P=0.007, 0.001 and 0.004, respectively). MPOT isolates were recovered from 46% of the collected blood specimens, whilst POT 122 isolates were recovered from 61% of the collected respiratory specimens (P=0.05).

CONCLUSION

The current study demonstrates that the easy, low-cost POT method is convenient for rapid delineation of A. baumannii clonal diversity in a tertiary-care hospital in Egypt.

Shifting trends and age distribution of ESKAPEEc resistance in bloodstream infection, Southwest China, 2012-2017

Background

ESKAPEEc contribute to a majority of bloodstream infections (BSIs) and their antibiogram have changed overtime, while data concerning about these alterations are lacking in China. Added that a paucity of studies referred to ESKAPEEc in pediatric BSIs, our study aimed to demonstrate the longitudinal alterations of ESKAPEEc distribution and antibiogram in adult and pediatric BSIs in Southwest China.

Methods

A multicenter retrospective surveillance study was launched from 2012 to 2017. Data of China Antimicrobial Resistance Surveillance System (CARSS) was analyzed by Whonet 5.6 and Graphpad Prism 6 Software. Chi-square test or Fisher’s exact test was used to examine and compare temporal changes.

Results

A total of 32,259 strains was isolated, with 17.4% from pediatric BSIs. ESKAPEEc contributed to 58.67% (18,924/32,259) of BSIs, with 65.3% of adult BSIs and 27.2% of pediatric BSIs. Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) were the two predominant species. Carbapenem resistance was prevalent in 0.76, 4.60, 9.47,13.66, 59.47% of E. coli, K. pneumoniae, Enterobacter cloacae, Pseudomonas aeruginosa (P. aeruginosa) and Acinetobacter baumannii (A. baumannii), respectively. The proportions of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREFM) were 28.91% and 2.20%, respectively. Between 2012-2014 and 2015–2017, E. coli and K. pneumonia showed significantly increased resistance rates to imipenem but decreased to ceftriaxone and ceftazidime, while A. baumannii exhibited reduced resistances to almost all the beta-lactams tested. The prevalence of antimicrobial resistance to most of agents against Gram-positive ESKAPEEc did not significantly varied during the same timeframe. In comparison with those from adult BSIs, K. pneumoniae from pediatric BSIs exhibited high resistance rates to all the beta-lactams tested, especially to carbapenems (12.79% vs 3.87%), while A. baumannii showed low resistance rates to all the agents.

Conclusions

Ongoing burden of ESKAPEEc in BSIs and increasing trend of imipenem resistance in E. coli and K. pneumoniae call for continued surveillance. Carbapenems are still active against Gram-negative ESKAPEEc, except for A. baumannii and vancomycin or linezolid is still effective against Gram-positive ESKAPEEc. Carbapenem-resistant K. pneumoniae in children and carbapenem-resistant A. baumannii in adults necessitate effective antimicrobial strategies in consideration of age stratification.

Extensively drug-resistant and pandrug-resistant Gram-negative bacteria in a tertiary-care hospital in Eastern India: A 4-year retrospective study

OBJECTIVES

Bacteria resistant to different classes of antimicrobial agents are a major threat to humanity and risk leading the world towards the return of the pre-antimicrobial era. This study was undertaken to detect the incidence of extensively drug-resistant (XDR) and pandrug-resistant (PDR) bacteria in a tertiary-care hospital in Bhubaneswar, Odisha, India.

METHODS

Positive bacterial cultures from different clinical samples were identified using a VITEK^®2 compact system and the antimicrobial susceptibility profile of different Gram-negative bacteria was analysed.

RESULTS

A total of 2489 clinical samples were collected and processed for culture during the period January 2013 to April 2017. Of 1103 pure bacterial cultures, 690 (62.6%) were Gram-negative bacteria. The antimicrobial susceptibility profile of Gram-negative bacterial strains revealed that 41.3% (n=285) were XDR and 8.1% (n=56) were PDR. Rates of colistin and tigecycline resistance were 16% and 51.9%, respectively.

CONCLUSION

This situation demands regular surveillance of antimicrobial resistance of Gram-negative bacteria and implementation of an efficient infection control programme.

Retrospective study on clonal relationship of multidrug-resistant Klebsiella spp. indicates closed circulation and initiation of clonal divergence

PURPOSE

Antibiotic resistance patterns often exhibit geographical variations. Periodic analyses of resistance spectra and phylogenetic trends are important guides for facilitating judicious use of therapeutic interventions. The present study retrospectively analysed the infection trends, resistance patterns, and clonal relationships between isolates of Klebsiella spp. from a tertiary care hospital.

METHODOLOGY

Bacterial isolates were collected from January 2013 to June 2014 and their resistance profiles were identified using an automated bacterial identification system. A phylogenetic tree was constructed using housekeeping genes with Molecular Evolutionary Genetic Analysis software. The dN/dS ratio was determined by the Synonymous Non-synonymous Analysis Program while polymorphic sites, and the difference per site was calculated using DNA Sequence Polymorphism software. Statistical Package for Social Science software was used to perform all statistical analyses.

KEY FINDINGS

The results of this study indicated the prevalence of community-acquired urinary tract and lower respiratory tract infections caused by Klebsiella spp. among geriatric patients. The occurrence of new allelic profiles, a low dN/dS ratio and the lack of strong evolutionary descent between isolates indicated that mutations play a major role in the evolution of the organism.

CONCLUSION

The findings of this study highlight the consequences of antimicrobial agents exerting a silent and strong selective force on the evolution of Klebsiella spp. The expansion of such analyses is of great importance for addressing rapidly emerging antibiotic-resistant opportunistic pathogens.

HR-LC-MS based analysis of two antibacterial metabolites from a marine sponge symbiont Streptomyces pharmamarensis ICN40

On the effort to screen antibiotics against Methicillin resistant Staphylococcus aureus (MRSA), an actinomycete strain which can produce bactericidal compound was isolated from a marine sponge of Kanyakumari Coast, India. Two anti-MRSA compounds (PVI401 and PVI402) were isolated from the fermentation plates of Streptomyces pharmamarensis ICN40. TLC bioautography analysis yielded two active spots with Rf value of 0.75 (PVI401) and 0.8 (PVI402) from the crude extract. Both the compounds were characterized by HR-LC-MS analysis. LC-MS based de-replication analysis found out the compound PVI401 with an exact mass of 376.09435 Da and PVI402 with an exact mass of 273.26795 Da were found to be unidentified. Antibacterial spectrum showed significant minimal inhibitory concentration as 0.5 μg/ml of PVI401 and 2 μg/ml of PVI402 against MRSA. The whole organism zebrafish safety evaluation exhibited the compound PVI402 is safe upto 1 mg/ml 40 μg/ml of PVI401 exhibited thrombosis in cardiac chamber and this compound exhibited 44 μg/ml of LC₅₀ against HepG2 hepatic carcinoma cell line. Both the compounds may be identified further for its structural novelty and clinical studies.