Risk factors in acquiring multidrug-resistant Klebsiella pneumoniae infections in a hospital setting in Saudi Arabia

Chlorhexidine and benzalkonium chloride: promising adjuncts in combating multidrug resistant Klebsiella pneumoniae in healthcare settings

BACKGROUND

Hospital-acquired infections caused by multidrug resistant (MDR) Klebsiella pneumoniae pose a significant global health threat. Effective antisepsis and disinfection protocols are mandatory to prevent these infections. This study aimed to isolate Klebsiella pneumoniae, evaluate antimicrobial susceptibility, and assess the efficacy of selected biocides.

METHODS

Fifty clinical MDR Klebsiella pneumoniae isolates were collected from various hospital departments. Antimicrobial susceptibility was determined using the disc diffusion method. Minimum inhibitory concentrations (MICs) of chlorhexidine and benzalkonium chloride were measured via agar dilution. Conventional PCR was employed to detect biocide resistance genes (qacE∆1 and cepA).

RESULTS

Klebsiella pneumoniae was identified in 19.16% of cases. All isolates exhibited multidrug resistance, with multiple antimicrobial resistance indices ranging from 0.24 to 0.92, reaching up to 1. Benzalkonium chloride MICs significantly increased with resistance, reaching up to 64 µg/mL, while chlorhexidine MICs were consistent across isolates. The qacE∆1 and cepA genes were detected in 62% and 72% of isolates, respectively, with a significant association between qacE∆1 and cephalosporin resistance. No significant correlation was found between biocide MICs and clinical specimen types or hospital units.

CONCLUSION

The cepA gene is closely associated with extensive drug resistance in Klebsiella pneumoniae, emphasizing its role in antimicrobial resistance. Optimized biocide formulations, when properly developed and applied, can play a crucial role in combating and preventing infections caused by multidrug-resistant Klebsiella pneumoniae.

Assessment of seasonal variations in antibiotic resistance genes and microbial communities in sewage treatment plants for public health monitoring

The spread of antimicrobial resistance (AMR) around the globe, especially in the urban cities with high population, is a major concern. Therefore, the current study aims at identifying antibiotic resistant bacteria, microbial community compositions and the quantification of antimicrobial resistant genes from six sewage treatment plants (STPs) across Pune city in Maharashtra, India. A total of 106 isolates obtained were tested against six antibiotics in which the highest resistance was observed against trimethoprim (24.53 %). The qPCR assays of seven antibiotic resistance genes revealed abundance of blaimp-1 and mecA genes in the summer and monsoon seasons followed by blaNDM-1 gene in the summer and winter seasons. The alpha diversity indices depicted highest microbial diversity of inlet samples during winter, followed by inlet samples during the summer and monsoon seasons. Comparative analysis revealed Bifidobacterium (51 %), Pseudomonas (28.7 %) and Zoogloea (17.6 %) as the most abundant genera in the inlet samples during the summer, monsoon and winter seasons respectively while Acinetobacter (31 %) and Flavobacterium (23 % in winter and 18.2 % in summer) dominated the outlet samples. The co-network analysis revealed positive and negative interactions in the winter and monsoon but only positive interactions in the summer season. Venn diagrams showed higher abundance of ASVs in the outlet samples than the inlet. The top genera correlated exactly opposite with the pH compared to BOD and COD. PICRUSt2-based functional prediction revealed a higher abundance of methicillin resistance, β-lactamase resistance and multidrug resistance genes in inlet samples while chloramphenicol resistance was found higher in outlet samples. Further, we observed that potential pathogens causing infectious disease such as pertussis, shigellosis and tuberculosis were present in all three seasons.

Unveiling the impact: COVID-19's influence on bacterial resistance in the Kingdom of Bahrain

BACKGROUND

Antibiotic resistance is a growing global health threat, and understanding local trends in bacterial isolates and their susceptibility patterns is crucial for effective infection control and antimicrobial stewardship. The coronavirus disease 2019 (COVID-19) pandemic has introduced additional complexities, potentially influencing these patterns.

AIM

To analyze trends in bacterial isolates and their antibiotic susceptibility patterns at Salmaniya Medical Complex from 2018 to 2023, with a specific focus on the impact of the COVID-19 pandemic on these trends.

METHODS

A retrospective analysis of microbiological data was conducted, covering the period from 2018 to 2023. The study included key bacterial pathogens such as Escherichia coli (E. coli), Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus, among others. The antibiotic susceptibility profiles of these isolates were assessed using standard laboratory methods. To contextualize the findings, the findings were compared with similar studies from other regions, including China, India, Romania, Saudi Arabia, the United Arab Emirates, Malaysia, and United States.

RESULTS

The study revealed fluctuating trends in the prevalence of bacterial isolates, with notable changes during the COVID-19 pandemic. For example, a significant increase in the prevalence of Staphylococcus aureus was observed during the pandemic years, while the prevalence of E. coli showed a more variable pattern. Antibiotic resistance rates varied among the different pathogens, with a concerning rise in resistance to commonly used antibiotics, particularly among Klebsiella pneumoniae and E. coli. Additionally, the study identified an alarming increase in the prevalence of multidrug-resistant (MDR) strains, especially within Klebsiella pneumoniae and E. coli isolates. The impact of the COVID-19 pandemic on these trends was evident, with shifts in the frequency, resistance patterns, and the emergence of MDR bacteria among several key pathogens.

CONCLUSION

This study highlights the dynamic nature of bacterial isolates and their antibiotic susceptibility patterns at Salmaniya Medical Complex, particularly in the context of the COVID-19 pandemic. The findings underscore the need for continuous monitoring and effective anti-microbial stewardship programs to combat the evolving threat of antibiotic resistance. Further research and policy initiatives are required to address the identified challenges and improve patient outcomes in the face of these ongoing challenges.

Insights into biofilm-mediated mechanisms driving last-resort antibiotic resistance in clinical ESKAPE pathogens

The rise of antibiotic-resistant bacteria poses a grave threat to global health, with the ESKAPE pathogens, which comprise Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. being among the most notorious. The World Health Organization has reserved a group of last-resort antibiotics for treating multidrug-resistant bacterial infections, including those caused by ESKAPE pathogens. This situation calls for a comprehensive understanding of the resistance mechanisms as it threatens public health and hinder progress toward the Sustainable Development Goal (SDG) 3: Good Health and Well-being. The present article reviews resistance mechanisms, focusing on emerging resistance mutations in multidrug-resistant ESKAPE pathogens, particularly against last-resort antibiotics, and describes the role of biofilm formation in multidrug-resistant ESKAPE pathogens. It discusses the latest therapeutic advances, including the use of antimicrobial peptides and CRISPR-Cas systems, and the modulation of quorum sensing and iron homeostasis, which offer promising strategies for countering resistance. The integration of CRISPR-based tools and biofilm-targeted approaches provides a potential framework for managing ESKAPE infections. By highlighting the spread of current resistance mutations and biofilm-targeted approaches, the review aims to contribute significantly to advancing our understanding and strategies in combatting this pressing global health challenge.

Bacteriophage-derived depolymerase: a review on prospective antibacterial agents to combat Klebsiella pneumoniae

Klebsiella pneumoniae is a Gram-negative bacterium that colonizes mucosal surfaces and is a common cause of nosocomial infections. The emergence of antimicrobial resistance in K. pneumoniae, particularly carbapenem-resistant strains, poses a significant threat to human health, with high mortality rates and healthcare costs. Another major problem is that hypervirulent K. pneumoniae tends to form biofilms. Bacteriophage-derived depolymerases, a class of enzymes that degrade diverse bacterial surface carbohydrates, have been exploited as antibiofilm and antimicrobial adjuvants because of their high stability, specificity, strong antimicrobial activity, and low incidence of bacterial resistance. This review presents a summary of the structure and properties of depolymerase, as well as an overview of both in vitro and in vivo studies of depolymerase therapy for multidrug-resistant or biofilm-forming K. pneumoniae infections. These studies employed a range of approaches, including utilizing a single depolymerase or combinations of depolymerase and phages or antibiotics. Furthermore, this review outlines the current challenges facing depolymerase therapy and potential future approaches for treating K. pneumoniae infections.

Distinct relative abundances in pathogens detected in mechanically ventilated patients with suspected pneumonia in the intensive care unit at King Abdulaziz University Hospital

In this study, we present for the first time the landscape of the lung microbiota in patients with ventilator-associated pneumonia in Intensive Care Units in Saudi Arabia. DNA from 83 deep endotracheal aspirate lung samples was subjected to PacBio sequencing to identify pathogens in comparison with conventional diagnostic techniques. Patients on ventilation with pneumonia presented with similar lung flora to those of patients on ventilation without pneumonia. Proteobacteria, Firmicutes, and Bacteroidetes were detected in the majority of the samples. Samples treated with different antibiotics exhibited similar abundances of phyla and families. In order, the ten most common species detected in 16 clusters were Klebsiella pneumoniae, Stenotrophomonas maltophilia, Haemophilus influenzae, Pseudomonas aeruginosa, Metamycoplasma salivarium, Elizabethkingia anophilis, Staphylococcus aureus, Acinetobacter baumannii, Prevotella oris and Klebsiella africana. Of 51 on ventilation with pneumonia, the pathogens identified through sequencing corresponded with the findings from culture-dependent tests in 26 patients (50.98%), whereas the results differed in 30 patients (58.82%). Of 32 patients on ventilation without pneumonia, the pathogens identified through sequencing matched the conventional diagnostics results in only two patients (6.25%) but differed in 25 patients (78.13%). In summary, patients on mechanical ventilation with pneumonia did not display notable phenotypic traits. K. pneumoniae and S. maltophilia were the most common taxa detected in the samples, although some variations in microbial composition were observed. We conclude that Intensive Care Units exhibit distinct patterns of microbial colonization.

Novel silver nanoparticle-based biomaterials for combating Klebsiella pneumoniae biofilms

Background

Klebsiella pneumoniae is a significant nosocomial pathogen that has developed resistance to multiple antibiotics, often forming biofilms that enhance its virulence. This study investigated the efficacy of a novel nanoformulation, AgNPs@chitosan-NaF, in combating K. pneumoniae biofilms.

Methods

Antimicrobial susceptibility testing was performed to assess the antibiotic resistance profile of K. pneumoniae isolates. The antibiofilm activity of AgNPs@chitosan-NaF was evaluated using crystal violet staining and scanning electron microscopy. The underlying mechanisms of action were investigated through gene expression analysis.

Results

The majority of K. pneumoniae isolates exhibited high levels of multidrug resistance. AgNPs@chitosan-NaF demonstrated superior biofilm inhibition compared to AgNPs@chitosan, significantly reducing biofilm biomass and disrupting biofilm architecture at MICs ranging from 0.125 to 1 μg/mL. Mechanistic studies revealed that the nanoformulation downregulated the expression of key biofilm-associated genes, including treC, fimA, mrkA, and ecpA. While AgNPs@chitosan-NaF exhibited a concentration-dependent cytotoxic effect on both normal and cancer cell lines, minimal cytotoxicity was observed at concentrations below 31.25 μg/mL.

Conclusion

This study highlights the synergistic effect of silver nanoparticles, chitosan, and sodium fluoride in combating K. pneumoniae biofilms. The nanoformulation, AgNPs@chitosan-NaF, emerges as a promising therapeutic strategy to address the challenge of multidrug-resistant bacterial infections.

The influence of efflux pump, outer membrane permeability and β-lactamase production on the resistance profile of multi, extensively and pandrug resistant Klebsiella pneumoniae

BACKGROUND

An important chance of nosocomial acquired infections are caused by the opportunistic bacterium Klebsiella pneumoniae. Urine, wound, sputum, and blood samples were collected from all patients. This study aimed to detect the antibiotic resistance profile, the frequency of MDR, XDR, PDR, and detection of efflux pump and outer membrane permeability genes in K. pneumoniae isolates.

METHODS

One hundred twenty samples were collected from patients who were admitted to the Ramadi Teaching Hospitals in Al-Anbar Governorate. Fifty five of K. pneumoniae strains were collected from patients. The VITEK®2 Compact B System was used to detect the antibiotic resistance pattern of studied bacteria. The isolates were classified as MDR, XDR, or PDR based on established guidelines. The data were analyzed using Clinical and Laboratory Standards Institute (CLSI) breakpoints. PCR was used to detect the efflux pumps and porins genes.

RESULTS

Out of the 120 samples studied, 45.83 % (55) tested positive for K. pneumoniae. The isolates displayed the greatest amount of resistance to cefazolin, ceftriaxone (98.2 %), ampicillin (100 %), and ceftazidime, cefepime (90.9 %). 20 % of the isolates were found to produce metallo-lactamases, and 41.81 % tested positive for extended-spectrum beta-lactamases. Overall, the rates of multi-drug resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) isolates were 57.2 %, 10.9 %, and 9.09 %, respectively. Additionally, the prevalence of efflux pump genes acrAB, mdtK, and tolC were 94.54 %, 14.54 %, and 89.09 %, respectively, while the porin-encoding genes ompK35 and ompK36 were found in 96.36 % and 98.18 % of the isolates.

CONCLUSION

This investigation concluded that the study isolates had a high degree of antibiotic resistance heterogenicity. High frequencies of resistance to ampicillin, cefazolin, and ceftriaxone are present in study isolates. Most strains were categorized as MDR strains, with six being XDR strains and five being PDR strains. One of the main routes of antibiotic resistance in multidrug-resistant K. pneumoniae strains is through the acrAB efflux system. The high prevalence of the acrAB, tolC, ompk35, and ompK36 genes were increases the ability of these isolates combat antimicrobial treatments.

Risk factors associated with multidrug-resistant Klebsiella pneumoniae infections: a multicenter observational study in Lebanese hospitals

BACKGROUND

Klebsiella pneumoniae is a significant global public health burden, especially in low-income countries and regions with fragile healthcare infrastructures, due to its ability to cause severe infections, increase mortality rates, and its rising antimicrobial resistance. This study aimed to estimate the proportion of multidrug-resistant (MDR) K. pneumoniae infections and identify associated risk factors.

METHODS

Data were retrospectively collected from three academic hospitals in Beirut, Lebanon, between January 2021 and September 2023 using a standardized form. Binary logistic regression was used to determine risk factors associated with MDR, extended-spectrum beta-lactamase (ESBL)-producing, and carbapenem-resistant K. pneumoniae (CRKP) infections.

RESULTS

Out of 2,655 K. pneumoniae cases, 410 met the inclusion criteria. The primary infection sources were the urinary tract (58.3%) and the respiratory tract (12.4%). Among the isolates, 61% were MDR K. pneumoniae, with 7.3% being extensively drug-resistant, and 0.5% pandrug-resistant. Additionally, 36.8% were ESBL-producing, while 6.3% were CRKP. Predictors significantly associated with MDR K. pneumoniae infections included male sex (adjusted odds ratio [AOR] = 3.46, 95% CI = 1.01-11.86, P = 0.04), recent antibiotics use (AOR = 4.52, 95% CI = 1.65-12.36, P = 0.003), and recent cancer chemotherapy (AOR = 3.43, 95% CI = 1.25-9.42, P = 0.01). ESBL-producing infections were associated with age ≥ 65 years, higher Charlson Comorbidity Index (CCI), and recent antibiotic use. CRKP infections were linked to male sex, prior antibiotic use, and longer hospital stays prior to infection (all P < 0.05).

CONCLUSIONS

MDR K. pneumoniae infections are steadily rising in Lebanon, along with an increase in ESBL-producing and CRKP cases. The main risk factors for MDR K. pneumoniae infections were male sex, recent antibiotic use, and cancer chemotherapy. ESBL-producing infections were associated with advanced age, higher CCI, and recent antibiotic use, while CRKP infections were linked to male sex, prior antibiotic use, and prolonged hospital stays. This situation is further exacerbated by inadequate healthcare infrastructure and suboptimal national surveillance. Strengthening local surveillance and implementing effective antibiotic stewardship programs are critical to managing this growing threat..

Characterization, Antibiotic Susceptibility, and Clonal Analysis of Carbapenem-Resistant Klebsiella pneumoniae From Different Clinical Cases

INTRODUCTION

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is recognized for its great ability to resist prescription drugs and its association with severe infections in humans.

OBJECTIVES

This study was designed to evaluate the characteristic resistance spectrum, to characterize the implicated carbapenem-resistant genes (CRGs), and to determine the extent of genetic diversity among Klebsiella pneumoniae isolates from human clinical cases in Duhok province.  Methodology: The VITEK-2 system was used to investigate the phenotypic antibiotic susceptibility of 23 K. pneumoniae isolated from distinct human clinical situations, multiplex PCR was used to assign the key common carbapenem-resistant genes (IMP, OXA48-like, bla-NDM, and KPC) in phenotypically carbapenem-resistant isolates, and the Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) assay was utilized to ascertain the clonal associations among those isolates.

RESULTS

Phenotypic resistance analysis revealed high resistance rates to various antibiotics, with all isolates exhibiting multidrug resistance (MDR). Coronavirus disease 2019 (COVID-19) patient isolates demonstrated significantly higher resistance compared to other sources. In addition, all isolates showed complete phenotypic resistance to carbapenems, PCR screening for CRGs identified blaOXA-48 as the predominant gene, present in all isolates. Genetic fingerprinting revealed diverse genotypes, with COVID-19 patient isolates exhibiting high similarity, contrasting with maximum diversity in non-COVID-19 clinical isolates.

Molecular Epidemiology and Antimicrobial Resistance of Extended-Spectrum β-Lactamase (ESBL)-Producing Klebsiella pneumoniae in Retail Cattle Meat

Enterobacteriaceae that produce extended-spectrum β-lactamases (ESBLs) can result in severe human infections, contributing to the development of complex diseases. Klebsiella pneumoniae is one of the ESBL-producing pathogens that helps to set antimicrobial resistance as a major public health problem worldwide. The current study aimed to isolate, identify, and characterize ESBL-producing K. pneumoniae and their antimicrobial resistance pattern in retail cattle meat samples. A comprehensive set of 225 cattle meat samples was gathered from 13 upazilas within the Sylhet district of Bangladesh. The bacterial isolates were obtained through biochemical and cultural techniques, and the identification of K. pneumoniae was accomplished using polymerase chain reactions (PCRs). Antimicrobial susceptibilities were assessed using disk diffusion in accordance with the Clinical and Laboratory Standards Institute (CLSI, 2020) guidelines. Genes encoding ESBL enzymes were detected by the double-disk synergy test (DDST) and multiplex PCR. The overall prevalence of Klebsiella spp. was 28.89% (65/225), whereas the positive percentage of K. pneumoniae was 59.2% (29/49) confirmed by PCR. Antimicrobial resistance was observed against 12 antibiotics. According to the phenotypic resistance pattern determined through the disk diffusion method, all isolates (100%) were resistant to ampicillin, amoxicillin, cefuroxime, cefotaxime, and colistin. On the other hand, the highest susceptibility was observed towards gentamicin (97.95%), followed by ciprofloxacin (85.71%), tetracycline (83.67%), and trimethoprim-sulfamethoxazole (81.63%). Out of the total K. pneumoniae isolates analyzed, ESBL genes were present, and the highest percentage, 82.8% (24/29), tested positive for bla TEM genes. Interestingly, among the nine ESBL genes, six were identified in K. pneumoniae isolates, except for bla OXA, bla CTX-M-grp2, and MultiCase DHA. The study's results reveal the presence of extended-spectrum β-lactamase (ESBL)-producing multidrug-resistant (MDR) K. pneumoniae in retail cattle meat samples posing a substantial public health threat.

Analysis of mcr family of colistin resistance genes in Gram-negative isolates from a tertiary care hospital in India

AIM

Colistin serves as the drug of last resort for combating numerous multidrug-resistant (MDR) Gram-negative infections. Its efficacy is hampered by the prevalent issue of colistin resistance, which severely limits treatment options for critically ill patients. Identifying resistance genes is crucial for controlling resistance spread, with horizontal gene transfer being the primary mechanism among bacteria. This study aimed to assess the prevalence of plasmid-mediated mcr genes associated with colistin resistance in Gram-negative bacteria, utilizing both genotypic and phenotypic tests.

METHODS AND RESULTS

The clinical isolates (n = 913) were obtained from a tertiary care center in Chennai, India. Colistin resistance was seen among Gram-negative isolates. These strains underwent screening for mcr-1, mcr-3, mcr-4, and mcr-5 genes via conventional PCR. Additionally, mcr-positive isolates were confirmed through Sanger sequencing and phenotypic testing. The bacterial isolates predominantly comprised Klebsiella pneumoniae (62.43%), Escherichia coli (19.71%), Pseudomonas aeruginosa (10.73%), and Acinetobacter baumannii (4.81%), along with other species. All isolates exhibited multidrug resistance to three or more antibiotic classes. Colistin resistance, determined via broth microdilution (BMD) using CLSI guidelines, was observed in 13.08% of the isolates studied. Notably, mcr-5 was detected in K. pneumoniae in PCR, despite its absence in Sanger sequencing and phenotypic tests (including the combined-disk test, colistin MIC in the presence of EDTA, and Zeta potential assays). This finding underscores the importance of employing multiple diagnostic approaches to accurately identify colistin resistance mechanisms.

Evolution of Antimicrobial Resistance in Klebsiella pneumoniae over 3 Years (2019-2021) in a Tertiary Hospital in Bucharest, Romania

BACKGROUND

The antimicrobial resistance (AMR) of Klebsiella pneumoniae recorded a steep upward trend over the last two decades, among which carbapenem-resistant Klebsiella pneumoniae (CRKP) is one of the most concerning strains considering the development and spread of AMR. The aim of this study was to analyze the evolution of AMR for Klebsiella pneumoniae and to describe the risk factors of AMR for Klebsiella pneumoniae, including the COVID-19 pandemic.

METHODS

We conducted a retrospective study on Klebsiella pneumoniae non-duplicative isolates collected from patients admitted to a tertiary hospital in Bucharest, Romania, from January 2019 to December 2021. We evaluated AMR changes by comparing resistance between 2019 and the mean of 2020-2021.

RESULTS

The rates of AMR increased for third-generation cephalosporins, carbapenems, aminoglycosides, fluoroquinolones, and colistin and decreased for trimethoprim/sulfamethoxazole (TMP/SMX), 45.7% in 2019 vs. 28.3% in 2021. A longer length of hospital stay (ꭓ2 = 49.68, p < 0.01); recent antibiotic consumption, RR = 1.38, 95% CI [1.21, 1.57]; and recent contact with hospital settings, RR = 1.54, 95% CI [1.32, 1.8] were risk factors for multidrug-resistant (MDR) Klebsiella pneumoniae.

CONCLUSIONS

The AMR of Klebsiella pneumoniae increased during 2020-2021 for most of the potential active antibiotics; only TMP/SMX resistance decreased, and it may represent a treatment option for CRKP or MDR Klebsiella pneumoniae infections. Decreasing the excessive use of antibiotics and the implementation of prevention and control measures in healthcare settings are mandatory for avoiding further increases in the AMR rate of Klebsiella pneumoniae.

Proteome analysis, genetic characterization, and antibiotic resistance patterns of Klebsiella pneumoniae clinical isolates

Klebsiella pneumoniae (K. pneumoniae) is a member of the ESKAPE group and is responsible for severe community and healthcare-associated infections. Certain Klebsiella species have very similar phenotypes, which presents a challenge in identifying K. pneumoniae. Multidrug-resistant K. pneumoniae is also a serious global problem that needs to be addressed. A total of 190 isolates were isolated from urine (n = 69), respiratory (n = 52), wound (n = 48) and blood (n = 21) samples collected from various hospitals in the Al-Qassim, Saudi Arabia, between March 2021 and October 2022. Our study aimed to rapidly and accurately detect K. pneumoniae using the Peptide Mass Fingerprinting (PMF) technique, confirmed by real-time PCR. Additionally, screening for antibiotic susceptibility and resistance was conducted. The primary methods for identifying K. pneumoniae isolates were culture, Gram staining, and the Vitek® 2 ID Compact system. An automated MALDI Biotyper (MBT) instrument was used for proteome identification, which was subsequently confirmed using SYBR green real-time polymerase chain reaction (real-time PCR) and microfluidic electrophoresis assays. Vitek® 2 AST-GN66 cards were utilized to evaluate the antimicrobial sensitivity of K. pneumoniae isolates. According to our results, Vitek® 2 Compact accurately identified 178 out of 190 (93.68%) K. pneumoniae isolates, while the PMF technique correctly detected 188 out of 190 (98.95%) isolates with a score value of 2.00 or higher. Principal component analysis was conducted using MBT Compass software to classify K. pneumoniae isolates based on their structure. Based on the analysis of the single peak intensities generated by MBT, the highest peak values were found at 3444, 5022, 5525, 6847, and 7537 m/z. K. pneumoniae gene testing confirmed the PMF results, with 90.53% detecting entrobactin, 70% detecting 16 S rRNA, and 32.63% detecting ferric iron uptake. The resistance of the K. pneumoniae isolates to antibiotics was as follows: 64.75% for cefazolin, 62.63% for trimethoprim/sulfamethoxazole, 59.45% for ampicillin, 58.42% for cefoxitin, 57.37% for ceftriaxone, 53.68% for cefepime, 52.11% for ampicillin-sulbactam, 50.53% for ceftazidime, 52.11% for ertapenem, and 49.47% for imipenem. Based on the results of the double-disk synergy test, 93 out of 190 (48.95%) K. pneumoniae isolates were extended-spectrum beta-lactamase. In conclusion, PMF is a powerful analytical technique used to identify K. pneumoniae isolates from clinical samples based on their proteomic characteristics. K. pneumoniae isolates have shown increasing resistance to antibiotics from different classes, including carbapenem, which poses a significant threat to human health as these infections may become difficult to treat.

Medical Device-Associated Biofilm Infections and Multidrug-Resistant Pathogens

Medical devices such as venous catheters (VCs) and urinary catheters (UCs) are widely used in the hospital setting. However, the implantation of these devices is often accompanied by complications. About 60 to 70% of nosocomial infections (NIs) are linked to biofilms. The main complication is the ability of microorganisms to adhere to surfaces and form biofilms which protect them and help them to persist in the host. Indeed, by crossing the skin barrier, the insertion of VC inevitably allows skin flora or accidental environmental contaminants to access the underlying tissues and cause fatal complications like bloodstream infections (BSIs). In fact, 80,000 central venous catheters-BSIs (CVC-BSIs)-mainly occur in intensive care units (ICUs) with a death rate of 12 to 25%. Similarly, catheter-associated urinary tract infections (CA-UTIs) are the most commonlyhospital-acquired infections (HAIs) worldwide.These infections represent up to 40% of NIs.In this review, we present a summary of biofilm formation steps. We provide an overview of two main and important infections in clinical settings linked to medical devices, namely the catheter-asociated bloodstream infections (CA-BSIs) and catheter-associated urinary tract infections (CA-UTIs), and highlight also the most multidrug resistant bacteria implicated in these infections. Furthermore, we draw attention toseveral useful prevention strategies, and advanced antimicrobial and antifouling approaches developed to reduce bacterial colonization on catheter surfaces and the incidence of the catheter-related infections.

Efficacy of Random Forest Models in Predicting Multidrug-Resistant Gram-Negative Bacterial Nosocomial Infections Compared to Traditional Logistic Regression Models

This study evaluates whether random forest (RF) models are as effective as traditional Logistic Regression (LR) models in predicting multidrug-resistant Gram-negative bacterial nosocomial infections. Data were collected from 541 patients with hospital-acquired Gram-negative bacterial infections at two tertiary-level hospitals in Urumqi, Xinjiang, China, from August 2022 to November 2023. Relevant literature informed the selection of significant predictors based on patients' pre-infection clinical information and medication history. The data were split into a training set of 379 cases and a validation set of 162 cases, adhering to a 7:3 ratio. Both RF and LR models were developed using the training set and subsequently evaluated on the validation set. The LR model achieved an accuracy of 84.57%, sensitivity of 82.89%, specificity of 80.10%, positive predictive value of 84%, negative predictive value of 85.06%, and a Yoden index of 0.69. In contrast, the RF model demonstrated superior performance with an accuracy of 89.51%, sensitivity of 90.79%, specificity of 88.37%, positive predictive value of 87.34%, negative predictive value of 91.57%, and a Yoden index of 0.79. Receiver operating characteristic curve analysis revealed an area under the curve of 0.91 for the LR model and 0.94 for the RF model. These findings indicate that the RF model surpasses the LR model in specificity, sensitivity, and accuracy in predicting hospital-acquired multidrug-resistant Gram-negative infections, showcasing its greater potential for clinical application.

Antibiotic Resistance, Biofilm Formation, and Persistent Phenotype of Klebsiella pneumoniae in a Vietnamese Tertiary Hospital: A Focus on Amikacin

Klebsiella pneumoniae stands out as a major opportunistic pathogen responsible for both hospital- and community-acquired bacterial infections. This study comprehensively assesses the antibiotic resistance, amikacin persistent patterns, and biofilm-forming ability of 247 isolates of K. pneumoniae obtained from an intensive care unit of a tertiary hospital in Vietnam. Microdilution assays, conducted on a 96-well plate, determined the minimum inhibitory concentrations (MICs) of amikacin. Susceptibility data for other antibiotics were gathered from the antibiogram profile. Stationary-phase bacteria were exposed to 50 × MIC, and viable bacteria counts were measured to determine amikacin persistence. Biofilm forming capacity on 96-well polystyrene surfaces was assessed by biomass and viable bacteria. The prevalence of resistance was notably high across most antibiotics, with 64.8% classified as carbapenem-resistant K. pneumoniae and 81.4% as multidrug resistant. Amikacin, however, exhibited a relatively low rate of resistance. Of the isolates, 58.2% demonstrated a moderate to strong biofilm formation capacity, and these were found to be poorly responsive to amikacin. K. pneumoniae reveals a significant inclination for amikacin persistence, with ∼45% of isolates displaying an antibiotic antibiotic-survival ratio exceeding 10%. The study sheds light on challenges in treating of K. pneumoniae infection in Vietnam, encompassing a high prevalence of antibiotic resistance, a substantial ability to form biofilm, and a notable rate of antibiotic persistence.

Enterobacter cloacae from urinary tract infections: frequency, protein analysis, and antimicrobial resistance

The genus Enterobacter belongs to the ESKAPE group, which includes Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. This group is characterized by the development of resistance to various antibiotics. In recent years, Enterobacter cloacae (E. cloacae) has emerged as a clinically important pathogen responsible for a wide range of healthcare-associated illnesses. Identifying Enterobacter species can be challenging due to their similar phenotypic characteristics. The emergence of multidrug-resistant E. cloacae is also a significant problem in healthcare settings. Therefore, our study aimed to identify and differentiate E. cloacae using Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) as a fast and precise proteomic analytical technique. We also tested hospital-acquired E. cloacae isolates that produce Extended-spectrum beta-lactamases (ESBL) against commonly used antibiotics for treating urinary tract infections (UTIs). We used a total of 189 E. cloacae isolates from 2300 urine samples of patients with UTIs in our investigation. We employed culturing techniques, as well as the BD Phoenix™ automated identification system (Becton, Dickinson) and Analytical Profile Index (API) system for the biochemical identification of E. cloacae isolates. We used the MALDI Biotyper (MBT) device for peptide mass fingerprinting analysis of all isolates. We utilized the single peak intensities and Principal Component Analysis (PCA) created by MBT Compass software to discriminate and cluster the E. cloacae isolates. Additionally, we evaluated the sensitivity and resistance of ESBL-E. cloacae isolates using the Kirby Bauer method. Out of the 189 E. cloacae isolates, the BD Phoenix system correctly identified 180 (95.24%) isolates, while the API system correctly identified 165 (87.30%) isolates. However, the MBT accurately identified 185 (98.95%) isolates with a score of 2.00 or higher. PCA positively discriminated the identified E. cloacae isolates into one group, and prominent peaks were noticed between 4230 mass-to-charge ratio (m/z) and 8500 m/z. The ESBL-E. cloacae isolates exhibited a higher degree of resistance to ampicillin, amoxicillin-clavulanate, cephalothin, cefuroxime, and cefoxitin. Several isolates were susceptible to carbapenems (meropenem, imipenem, and ertapenem); however, potential future resistance against carbapenems should be taken into consideration. In conclusion, MALDI-TOF MS is a powerful and precise technology that can be routinely used to recognize and differentiate various pathogens in clinical samples. Additionally, the growing antimicrobial resistance of this bacterium may pose a significant risk to human health.

Synthesis, design, and antimicrobial activity of pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidinones based on quinoline derivatives

The pyrido[2,3‐d]pyrimidine moieties are one of the most biologically widespread heterocyclic compounds as antimicrobial, antioxidant, antitubercular, antiviral and anti‐inflammatory. Hence, we synthesized an efficient new series of 2‐thioxo‐pyrido[2,3‐d]pyrimidinone, 2‐hydrazinyl‐(quinolin‐2‐yl)pyrido[2,3‐d]pyrimidinone,N′‐(quinolin‐2‐yl)‐pyrido[2,3‐d]pyrimidine‐(formo/aceto)‐hydrazide and substituted‐(quinolin‐2‐yl)pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidinone derivatives. The characterization of new compounds was corresponded by using spectroscopic techniques, IR, NMR and Mass spectra. In vitro, all compounds were evaluated as antimicrobial activity compared with cefotaxime sodium and nystatin as the standard drug. This work deals with the exploration of the new heterocyclic compounds and medicinal diversity of quinoline‐pyrido[2,3‐d][1,2,4]triazolo[4,3‐a]pyrimidine derivatives that might pave the way for long in the discovery of therapeutic medicine for future drug design.