Extended-spectrum Beta-lactamase Research Articles

Isolation ofaerobic bacteria from surgical site infections following orthopaedic operations incats and dogs.

Surgical site infections (SSIs) cause significant complications inthe postoperative period inveterinary surgeries. Determining the aetiology ofinfections iscrucial for increasing treatment success rates. This study aims toassess treatment processes byidentifying the bacterial agents responsible for infections occurring incats and dogs after orthopaedic operations and todetermine the antimicrobial resistance profiles ofthese agents. Strains isolated from SSIs were retrospectively analysed inpatients brought tothe Surgical Clinic ofSiirt University Animal Health Application and Research Hospital between 2021 and 2023. The isolates were identified using MALDI-TOF MS. The disc diffusion method was applied todetermine the antimicrobial susceptibility ofthe isolates. Ahigh isolation rate was detected inmethicillin-resistant Staphylococcus pseudintermedius and extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae. According tothe antimicrobial susceptibility results, cephalosporin treatment was continued inonly one ofthe cases inwhich prophylactic treatment with cephalosporin group antibiotics was applied. Consequently, this study revealed that preoperative prophylactic antibiotic administration may not besufficient inpreventing surgical site infections. Diagnosis ofaetiological agents and evaluation ofantimicrobial susceptibility are essential inpreventing surgical site infections and determining effective treatment options.

Typical pneumonia among human immunodeficiency virus-infected patients in public hospitals in southern Ethiopia.

Typical pneumonia is a pressing issue in the treatment of human immunodeficiency virus (HIV) patients, especially in Sub-Saharan Africa, where it remains a significant menace. Addressing this problem is crucial in improving health outcomes and the reduction of the burden of diseases in this vulnerable category of patients. To determine the prevalence of community-acquired typical pneumonia among HIV patients in Public Hospitals in southern Ethiopia. A cross-sectional study was done among 386 HIV patients clinically suspected of typical pneumonia attending the anti-retroviral therapy (ART) clinics of two hospitals from March to September 2022. A pretested structured questionnaire was employed to collect the demographic, clinical, and behavioral data. Sputum samples were collected and inspected for bacteria following standard procedures, and antimicrobial susceptibility testing was performed employing the Kirby-Bauer disk diffusion method. Besides, extended-spectrum β-lactamase (ESβL) and carbapenemase-producing Gram-negative bacteria were inspected by the double disk synergy test and modified carbapenem inactivation method. Descriptive and inferential statistical analyses were also done. Overall, 39.1% (151/386) of sputum cultures (95% Confidence Interval: 32.4-44) were bacteriologically positive. A total of 151 bacteria were identified, comprising 72.8% (n = 110) of Gram-negative bacteria. The predominant isolate was Klebsiella pneumoniae (25.8%, n = 39), followed by Staphylococcus aureus (17.9%, n = 27); 59.6% (n = 90) of the entire isolates were multidrug-resistant (MDR). Forty percent (11/27) of S. aureus were methicillin-resistant S. aureus (MRSA), and 28.1% (n = 31) and 20.9% (n = 23) of Gram-negative bacteria were extended-spectrum beta-lactamases (ESBL) and carbapenemase producers, respectively. Occupational status, alcohol consumption, cluster of differentiation4 (CD4) Thymocyte cell count < 350, interruption of trimethoprim-sulfamethoxazole prophylaxis and antiretroviral treatment, and recent viral load ≥ 150 were found statistically significant. The higher rates of MDR, MRSA, ESBL, and carbapenem-resistant Enterobacterales (CRE) indicate that bacterial pneumonia is a vexing problem among HIV patients and therefore it is advisable to implement an antimicrobial stewardship program in the study area.

Acute Respiratory Distress Syndrome in a Patient with Myasthenia Gravis and Septic Shock: A Case Report

Introduction: Myasthenia gravis (MG) is an autoimmune disorder characterized by muscle weakness, often affecting respiratory and oropharyngeal muscles. This predisposition to respiratory compromise, coupled with impaired swallowing and the potential need for immunosuppressive therapies, increases the risk of pneumonia and subsequent sepsis in MG patients. Sepsis, in turn, is a significant risk factor for acute respiratory distress syndrome (ARDS), a severe lung condition with high mortality. Case presentation: We present the case of a 47-year-old male with a 4-year history of MG who was admitted to our hospital with progressive dyspnea and dysphagia. His condition deteriorated rapidly, leading to septic shock and respiratory failure necessitating invasive mechanical ventilation. Blood cultures identified Klebsiella pneumoniae with extended-spectrum beta-lactamase (ESBL) production. Despite aggressive treatment, including therapeutic plasma exchange (TPE), the patient's hospital course was complicated. Conclusion: This case underscores the critical importance of vigilant monitoring and early intervention in MG patients presenting with respiratory symptoms or signs of infection. Prompt recognition and aggressive management of sepsis are crucial to mitigate the risk of ARDS and improve outcomes in this vulnerable patient population.

Distribution of ESBL-producing and non-ESBL-producing Klebsiella pneumoniae isolated from sputum specimens in the Zainoel Abidin General Hospital, Banda Aceh, Indonesia

Abstract. Suhartono S, Hayati Z, Mahdani W, Andini F. 2024. Distribution of ESBL-Producing and Non-ESBL-Producing Klebsiella pneumoniae isolated from sputum specimens in the Zainoel Abidin General Hospital, Banda Aceh, Indonesia. Biodiversitas 25: 3247-3254. Klebsiella pneumoniae, a significant nosocomial pathogen, particularly in the case of strains producing extended-spectrum beta-lactamase (ESBL), was the focus of this study. The study aimed to determine the distributions stratified by patients’ age, sex, hospital wards, and the antimicrobial susceptibility pattern of ESBL and non-ESBL K. pneumoniae isolated from expectorate sputum at Zainoel Abidin General Hospital (RSUD dr. Zainoel Abidin), Banda Aceh, Indonesia, from January 2021 to January 2024. The prevalence of ESBL-producing K. pneumoniae was 79.84% (103/129 isolates), with the highest incidence found in patients aged &gt;45 years (74.76%) and males (67.96%). The prevalence of non-ESBL-producing K. pneumoniae was 20.16% (26 isolates), with the highest incidence in patients aged &gt;45 years (76.92%) and males (62.23%). The surgical ward had the highest incidence of ESBL-producing K. pneumoniae (14.56%), followed by the cardiopulmonary ward (14.56%). The cardiopulmonary ward also had the highest incidence of non-ESBL-producing K. pneumoniae (38.47%). The ESBL-producing K. pneumoniae isolates were more sensitive to amikacin than non-ESBL isolates, while the non-ESBL-producing K. pneumoniae isolates were sensitive to cefotaxime, amikacin, and tobramycin. The increasing prevalence of ESBL-producing K. pneumoniae underscores the significance of the study's findings, providing valuable insights into the epidemiology and antibiotic susceptibility profiles of K. pneumoniae in this clinical setting and the importance of reasonable antibiotic use.

Prevalence and characterization of quinolone resistance and integrons in clinical Gram-negative isolates from Gaza strip, Palestine.

Gram-negative bacteria with quinolone resistance and extended-spectrum beta-lactamases (ESBLs) present significant treatment challenges. This study evaluated the prevalence and characteristics of quinolone resistance in Gram-negative strains, investigating the relationship between plasmid-mediated quinolone resistance (PMQR), ESBLs, and integrons. We collected 146 Gram-negative isolates from patients in three Palestinian hospitals. For quinolone resistance isolates, the presence and characterization of PMQR, β-lactamase genes and integrons were studied by PCR and sequencing. Out of 146 clinical isolates, 64 (43.8%) were resistant to quinolones, with 62 (97%) being multidrug-resistant (MDR) and 33 (51.5%) ESBL-producers. PMQR-encoding genes were present in 45 (70.3%) isolates, including aac(6')-Ib-cr (26.6%), qnrA (18.8%), qnrS1 (20.8%), and qnrB (6.4%). BlaCTX-M genes were detected in 50% (32/64) of isolates, with blaCTX-M-15 being the most common. BlaTEM-1, blaSHV-1 and blaVIM genes were found in 13, 6, and 4 isolates, respectively. Class I integrons were found in 31/64 (48%) of isolates, with 14 containing gene cassettes conferring resistance to trimethoprim (dhfr17, dfrA12, dfrA1) and aminoglycosides resistance genes (aadA1, aadA2, aadA5, and aadA6). This study found a high rate of quinolone resistance, ESBL and integrons in clinical Gram-negative isolates from our hospitals. Urgent measures are crucial, including implementing an antimicrobial resistance surveillance system, to control and continuously monitor the development of antimicrobial resistance.

A Pilot Analysis for a Multicentric, Retrospective Study on Biodiversity and Difficult-to-Treat Pathogens in Burn Centers across the United States (MICROBE).

Following burn injury, patients are at increased risk of infection and are often cited as having a high incidence of difficult-to-treat pathogens (DTp). The purpose of this study is to determine the incidence of DTp after burn injury, which factors are associated with their development, and subsequent outcomes. This single-center, retrospective study assessed patients with thermal or inhalation injury who had a positive culture resulting in initiation of treatment (i.e., excision, topical, or systemic antimicrobials). Demographic data, pathogen and resistance profiles, and prior exposure to topical and systemic antimicrobials were collected. Pathogens were considered DTp if they were multi-drug-resistant (MDR), extensively drug-resistant (XDR), methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL)-producing, AmpC-producing, carbapenem-resistant, difficult-to-treat resistance (DTR) Pseudomonas sp., carbapenem-resistant Acinetobacter baumannii (CRAB), or Stenotrophomonas spp. Sixty-five patients who grew 376 pathogens were included in the final analysis. Two-hundred thirteen (56.7%) pathogens were considered DTp. Prior exposure to 7 of the 11 collected topical antimicrobials and 9 of 11 systemic antimicrobial classes were significantly associated with future development of a DTp. This remained true for six and eight, respectively, after controlling for significant covariates via logistic regression. As there were only four deaths, a Cox-proportional hazard analysis was not feasible. The Kaplan-Meier plot according to DTp revealed a clear divergence in mortality (Log rank p = 0.0583). In this analysis, exposure to topical and systemic antibiotics was associated with the development of DTp. The results from this pilot study will inform the next iteration of multicenter study.

Effects of household concrete floors on maternal and child health - the CRADLE trial: a randomised controlled trial protocol.

Early life soil-transmitted helminth infection and diarrhea are associated with growth faltering, anemia, impaired child development, and mortality. Exposure to fecally contaminated soil inside the home may be a key contributor to enteric infections, and a large fraction of rural homes in low-income countries have soil floors. The objective of this study is to measure the effect of installing concrete floors in homes with soil floors on child soil-transmitted helminth infection and other maternal and child health outcomes in rural Bangladesh. The Cement-based flooRs AnD chiLd hEalth (CRADLE) trial is an individually randomised trial in Sirajganj and Tangail districts, Bangladesh. Households with a pregnant woman, a soil floor, walls that are not made of mud will be eligible, and no plan to relocate for 3 years. We will randomise 800 households to intervention or control (1:1) within geographic blocks of 10 households to account for strong geographic clustering of enteric infection. Laboratory staff and data analysts will be blinded; participants will be unblinded. We will install concrete floors when the birth cohort is in utero and measure outcomes at child ages 3, 6, 12, 18, and 24 months. The primary outcome is prevalence of any soil-transmitted helminth infection (Ascaris lumbricoides, Necator americanus, or Trichuris trichiura) detected by qPCR at 6, 12, 18, or 24 months follow-up in the birth cohort. Secondary outcomes include household floor and child hand contamination with E. coli, extended-spectrum beta-lactamase producing E. coli, and soil-transmitted helminth DNA; child diarrhea, growth, and cognitive development; and maternal stress and depression. Study protocols have been approved by institutional review boards at Stanford University and the International Centre for Diarrheal Disease Research, Bangladesh (icddr,b). We will report findings on ClinicalTrials.gov, in peer-reviewed publications, and in stakeholder workshops in Bangladesh. NCT05372068, pre-results.

Antimicrobial Resistance and Phenotypic Detection of Extended Spectrum Beta-Lactamase in Escherichia coli from Children with Cases of Diarrhea in Nasarawa-South, Nasarawa State, Nigeria

Antimicrobial Resistance and Phenotypic Detection of Extended Spectrum Beta-Lactamase in Escherichia coli from Children with Cases of Diarrhea in Nasarawa-South, Nasarawa State, Nigeria

Perceptions of Carriership of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Bacteria: A Qualitative Study.

The spread of antimicrobial resistance is a global health concern, and resistance mediated by Extended-Spectrum Beta-Lactamases (ESBLs) can cause major consequences. The aim of this study was to explore individuals' perceptions of their daily life and how they cope after being diagnosed with carriage of ESBL-producing bacteria. A qualitative study was conducted with a descriptive design. Data were collected through individual interviews with 24 persons having ESBL carriership, via a semi-structured interview guide. The data were analyzed using qualitative content analysis. The informants' perceptions on "Living with uncertainty about carriership that impacts oneself and others" were interpreted. Experiences of altered behaviors and sentiments due to ESBL carriership were described, as ESBL carriership was perceived to have a psychosocial impact on many informants. Ambiguous and inconsistent information tended to exacerbate these perceptions. The results of this study emphasize the importance of conveying individualized information, both at the time of diagnosis of ESBL carriage and thereafter. This study was not registered.

Rough Ag2S@H-CeO2 photonic nanocomposites for effective eradication of drug-resistant bacteria and improved healing of infected cutaneous wounds

With the continuous increasing threat of drug-resistant bacteria induced cutaneous wound infections, there is a growing demand for novel effective antibiotics-alternative antibacterial strategies for clinical anti-infective therapy. Here, we report the fabrication and antibacterial efficacy of Ag2S@H-CeO2 photonic nanocomposites with rough surface through in-situ growth of Ag2S nanoparticles on CeO2 hollow spheres. With excellent photothermal property and peroxidase-like activity, as well as increased bacterial adhesion, the photonic nanocomposites demonstrated a broad-spectrum synergistic antibacterial effect against Gram-positive, Gram-positive bacteria and fungi as well biofilm in vitro. Significantly, the nanocomposites can effectively eradicate drug-resistant bacteria such as Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Gram-negative extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli). Notably, in vivo assessments validated its synergistic therapeutic potential in the treatment of MRSA-infected cutaneous wounds, all while maintaining excellent biosafety and biocompatibility. Our study offers a competitive and promising strategy for the development of a multifunctional synergistic antibacterial platform poised to effectively treat drug-resistant bacteria-infected cutaneous wounds.

Analysis of antibiotic resistance in Gram-negative bacilli in wild and exotic healthy birds in Brazil: A warning sign

Bacterial antibiotic resistance is a public health problem affecting humans and animals. This study focuses on identifying Gram-negative bacilli (GNB) (MALDI-TOF MS and Klebsiella MALDI TypeR) resistant to antimicrobials in freshly emitted feces of healthy captive and rescued wild birds from a zoo in Brazil. Birds from the zoo and rescued from sixteen different orders were investigated. Resistant bacteria from feces were selected (MacConkey agar with 2 μg/mL cefotaxime). Genomic similarity and plasmid were investigated by Pulsed-Field Gel Electrophoresis of XbaI fragments (XbaI-PFGE) and S1-PFGE. Polymerase Chain Reaction (PCR) was performed to search for beta-lactamase genes. From 80 birds included, 26 from the zoo (50 %) and 18 rescued wild birds (64 %) presented cefotaxime-resistant GNB. E. coli and Klebsiella spp were the most prevalent species. Among 65 isolates from the zoo and rescued wild birds, 75 % were considered multidrug-resistant (MDR). The majority of the isolates were extended-spectrum beta-lactamases (ESBL) producing and resistant to enrofloxacin. blaCTX-M-GROUP-1, blaTEM, and blaSHV were the most detected genes, and blaKPC was detected in K. pneumoniae complex. According to genomic similarity results, some identical profiles were found in birds with no known contact among the zoo or rescued birds. Several isolates carried one to three plasmids (15–350 kb). The presence of multidrug-resistant (MDR) isolates from healthy captive and wild birds brings novel data on the dissemination of these elements to the environment.

Antibiotic resistance and its correlation with biofilm formation and virulence genes in Klebsiella pneumoniae isolated from wounds.

Klebsiella pneumoniae is the most important species of the Klebsiella genus and often causes hospital infections. These bacteria have a high resistance to most of the available drugs, which has caused concern all over the world. In this study, we investigated the antibiotic resistance profile and the ability to produce extended-spectrum beta-lactamase (ESBL) among K. pneumoniae isolates, and then we investigated the relationship between these two factors with biofilm formation and the prevalence of different virulence genes. In this study, 130 isolates of K. pneumoniae isolated from wounds were investigated. The antibiotic resistance of the isolates was evaluated by the disk diffusion method. The microtiter plate method was used to measure biofilm formation. The prevalence of virulence genes was detected by multiplex PCR. Among the examined isolates, 85.3% showed multidrug resistance. 87.6% of the isolates were ESBL-positive. Imipenem, meropenem, and fosfomycin were the most effective drugs. The ability of the isolates to produce biofilm was strong (80%), moderate (12.3%), and weak (7.6%), respectively. fimH, mrKD, entB, and tolC virulence genes were observed in all isolates. High prevalence of antibiotic resistance (especially multidrug resistance), high prevalence of ESBL-producing isolates, the ability of all isolates to biofilm formation, and the presence of fimH, mrKD, entB, and tolC virulence genes in all isolates show the importance of these factors in the pathogenesis of K. pneumoniae isolates in Iraq.

Efficacy of Nitrofurantoin and Fosfomycin against Extended Spectrum Beta Lactamase Producing Uropathogens in the Era of Antibiotic Resistance: A Cross-sectional Study

Background: Urinary Tract Infection (UTI) is one of the most common bacterial infections that require medical care. It accounts for 25% of all infections. Limited number of antibiotics are available for the treatment of UTI due to increased resistance among uropathogens. Aim of the study is to determine the causative agents of UTI and to evaluate the action of nitrofurantoin and fosfomycin against Enterobacteriaceae in ESBL (Extended spectrum beta-lactamase) producing strains. Material and Methods: It is a retrospective study carried out in the department of Microbiology, MAMC, Agroha. Data related to urine culture and antibiotic susceptibility pattern from January 2023 to December 2023 was taken from the records and analysed. Results: Out of 1648 urine samples processed, 569 showed significant bacterial growth. Escherichia coli (45.3%) was the most common isolate followed by Klebsiella pneumoniae (20.5%), Enterococcus (17.2%), Staphylococcus aureus (5%). Among the gram negative bacilli, 40% were ESBL producers. These ESBL producing strains were 99% sensitive to Fosfomycin and 75% sensitive to Nitrofurantoin. Conclusion: The study revealed that Nitrofurantoin and Fosfomycin are very effective oral drugs for empirical treatment against gram negative uropathogens causing UTI, especially multi drug resistant strains.

Comparison of Mutant Prevention Concentrations of Fluoroquinolones Against ESBL-Positive and ESBL-Negative Klebsiella pneumoniae Isolates from Orthopedic Patients.

The majority of Klebsiella pneumonia isolates possess the extended-spectrum beta-lactamase (ESBL) enzymes. Therefore, K. pneumoniae can easily develop drug resistance. How to effectively overcome the problem of drug resistance in K. pneumoniae is still a research hotspot. This study aimed to compare the mutant prevention concentration (MPC) of ESBL-positive and ESBL-negative K. pneumoniae isolated from orthopedic patients, which may provide a basis for the effective use of drugs to control the enrichment of resistance mutants of K. pneumoniae. The MPC90 values of 55 isolates of ESBL-positive K. pneumoniae against 4 fluoroquinolones were 32 µg/mL for levofloxacin and gatifloxacin, 16 µg/mL for ciprofloxacin, and 4 µg/mL for gemifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin and 2 for gemifloxacin and gatifloxacin, respectively. For ESBL-negative K. pneumoniae isolates, the MPC90 values were 16 µg/mL for levofloxacin and ciprofloxacin, 4 µg/mL for gemifloxacin, and 32 µg/mL for gatifloxacin. The selection index value was 8 for levofloxacin and ciprofloxacin, 2 for gemifloxacin, and 4 for gatifloxacin. For the ESBL-positive K. pneumoniae, the %T>MIC90 order was gemifloxacin > levofloxacin > ciprofloxacin > gatifloxacin. For the ESBL-negative K. pneumoniae, the %T>MIC90 order was levofloxacin > gemifloxacin > ciprofloxacin > gatifloxacin. The mutant-preventing ability of gatifloxacin and gemifloxacin was the strongest among the 4 fluoroquinolones. So gemifloxacin may be the first choice of drug to treat K. pneumoniae infection.

Prevalence of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae and Associated Clinical Implications at the University Teaching Hospital of Kigali in Rwanda.

Extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae poses a global problem and complicates therapeutic choices. The paucity of data in resource-poor countries undermines the understanding of the problem's extent, and cases of antimicrobial treatment failure continue to accumulate. This study aimed to determine the prevalence and clinical implications of ESBL-producers at the University Teaching Hospital of Kigali in Rwanda. A 1-year cross-sectional retrospective study was conducted on Escherichia coli and Klebsiella pneumoniae isolated in blood and urine from January 1 to December 31, 2022. In total, 1,283 isolates were recorded. The results showed an overall prevalence of ESBL phenotypes at 300/1,283 (23.4%). Extended spectrum beta-lactamase-positive E. coli was more frequently detected than K. pneumoniae in both urine (20.6% versus 10.1%) and blood (8.8% versus 6.2%). These isolates were 100% resistant to amoxicillin-clavulanic acid, third-generation cephalosporins, piperacillin, sulbactam ampicillin, ampicillin, cefuroxime, and cefoxitin. The least resistance was observed to amikacin (18%), meropenem (10%), and polymyxin B (3%). Hospital stays ranging from 8 to 21 days were the most frequent, and the mortality rate was 10.3% in patients with ESBL cases, which was more than double the general hospital mortality rate in the same period. In conclusion, our findings indicate a high prevalence of ESBL phenotypes, high antibiotic resistance rates, prolonged hospital stays, and an increased mortality rate. These findings suggest the need for continued surveillance, planning appropriate interventions, and caution during empirical therapy.

PREVALENCE OF ASYMPTOMATIC BACTERIURIA IN ANTENATAL WOMEN ATTENDING TERTIARY CARE HOSPITAL-A CROSS-SECTIONAL STUDY

Objective: Urinary tract infection (UTI) is one of the most common bacterial infections during pregnancy due to anatomical changes and physiological adaptations during pregnancy. Asymptomatic bacteriuria is the significant presence of bacteria in the urine of an individual without symptoms. Untreated asymptomatic bacteriuria (ASB) in pregnancy predisposes to symptomatic UTI in 25% of infected women. Screening of antenatal women help in early diagnosis and treatment of ASB and thus to prevent maternal and fetal morbidity and mortality. The present study was carried out to determine the prevalence of UTI in pregnant women and to study the bacteriological profile and antimicrobial sensitivity patterns of uropathogens. Methods: A Cross-sectional study was conducted for a period of six months and midstream urine specimens were collected from 480 pregnant females and were processed by standard protocols. All subjects were clinically identified to have no signs and symptoms of UTI. Antibiotic susceptibility testing was done as per CLSI guidelines. Results: Prevalence rate of asymptomatic bacteriuria was seen 10% in pregnant women. Majority of the culture-positive patients belonged to the age group of 26-30 y (31.25%). 70.84% were Gram-negative isolates and 29.16% were Gram-positive organisms. The commonest pathogen isolated was Escherichia coli (33.33%). In the present study, Extended Spectrum Beta-Lactamase (ESBL) production was seen in (20.58%) isolates, and Metallo Beta-Lactamase (MBL) production was seen in (17.64%) isolates. Conclusion: This study reveals the importance of screening of pregnant women for UTI. Emerging multi-drug resistance seen in uropathogens emphasizes the need to rationalize use of antibiotics, which eventually prevent development of resistant strains.

Colistin resistance in ESBL- and Carbapenemase-producing Escherichia coli and Klebsiella pneumoniae clinical isolates in Cambodia

Despite the critical importance of colistin as a last-resort antibiotic, limited studies have investigated colistin resistance in human infections in Cambodia. This study aimed to investigate the colistin resistance and its molecular determinants among Extended-spectrum beta-lactamase (ESBL)- and carbapenemase-producing (CP) Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli) isolated in Cambodia between 2016 and 2020. E. coli (n = 223) and K. pneumoniae (n = 39) were tested for colistin minimum inhibitory concentration (MIC) by broth microdilution. Resistant isolates were subjected to polymerase chain reaction (PCR) for detection of mobile colistin resistance genes (mcr) and chromosomal mutations in the two-component system (TCS). Eighteen isolates (10 K. pneumoniae and 8 E. coli) revealed colistin resistance with a rate of 5.9% in E. coli and 34.8% in K. pneumoniae among ESBL isolates, and 1% in E. coli and 12.5% in K. pneumoniae among CP isolates. The resistance was associated with mcr variants (13/18 isolates, mcr-1, mcr-3, and mcr-8.2) and TCS mutations within E. coli and K. pneumoniae, with the first detection of mcr-8.2 in Cambodia, the discovery of new mutations potentially associated to colistin resistance in the TCS of E. coli (PhoP I47V, PhoQ N352K, PmrB G19R, and PmrD G85R) and the co-occurrence of mcr genes and colistin resistance conferring TCS mutations in 11 of 18 isolates. The findings highlight the presence of colistin resistance in ESBL- and CP- Enterobacteriaceae involved in human infections in Cambodia as well as chromosomal mutations in TCS and the emergence of mcr-8.2 in E. coli and K. pneumoniae. It underscores the need for continuous surveillance, antimicrobial stewardship, and control measures to mitigate the spread of colistin resistance.

Bloodstream infections due to multi-drug resistant bacteria in the emergency department: prevalence, risk factors and outcomes-a retrospective observational study.

Multidrug-resistant organisms (MDROs) are prevalent in patients admitted to the Emergency Department (ED) and increase the risk of inappropriate empirical antibiotic therapy. Risk stratification for MDRO infection is essential to early identify patients requiring empirical broad-spectrum antibiotic therapy, but it remains challenging for emergency physicians. This study aimed to evaluate prevalence, risk factors, and outcomes of patients admitted to the ED with a bloodstream infection (BSI) caused by MDROs. A retrospective observational study enrolling all consecutive adult patients admitted with a BSI to the ED of Niguarda Hospital, Italy, from January 2019 to December 2021 was performed. 757 patients were enrolled, 14.1% with septic shock. 156 (20%) patients had a BSI caused by MDRO: extended-spectrum beta-lactamase (ESBL) producing Enterobacterales were the most prevalent followed by methicillin-resistant Staphylococcus aureus (MRSA). Risk factors for BSI due to MDRO and specifically for ESBL were chronic renal failure (OR 2.2; 95%CI 1.4-3.6), nursing home residency (OR 4.4; 95%CI 1.9-10.2) and antibiotic therapy in the last 90-days (OR 2.6; 95%CI 1.7-4), whereas for MRSA were dialysis (OR 12.3; 95%CI 1.8-83), antibiotic therapy and/or hospital admission in the past 90-days (OR 3.6; 95%CI 1.2-10.6) and ureteral stent or nephrostomy (OR 7.8; 95%CI 1.5-40.9). Patients with BSI due to MDRO had a higher rate of inappropriate empirical antibiotic therapy (50%) and longer length of stay, but no higher in-hospital mortality. Among patients admitted to the ED with a BSI, MDROs are frequent and often associated with inappropriate empirical antibiotic therapy. Specific updated risk factors for MDRO may help clinicians to better identify patients requiring a broader antibiotic therapy in the ED, while awaiting microbiological results.

Comprehensive genomics reveals novel sequence types of multidrug resistant Klebsiella oxytoca with uncharacterized capsular polysaccharide K- and lipopolysaccharide O-antigen loci from the National Hospital of Uganda

The Klebsiella oxytoca complex comprises diverse opportunistic bacterial pathogens associated with hospital and community-acquired infections with growing alarming antimicrobial resistance. We aimed to uncover the genomic features underlying the virulence and antimicrobial resistance of isolates from Mulago National Hospital in Uganda. We coupled whole genome sequencing with Pathogenwatch multilocus sequence typing (MLST) and downstream bioinformatic analysis to delineate sequence types (STs) capsular polysaccharide K- and O-antigen loci, along with antimicrobial resistance (AMR) profiles of eight clinical isolates from the National Referral Hospital of Uganda. Our findings revealed that only two isolates (RSM6774 and RSM7756) possess a known capsular polysaccharide K-locus (KL74). The rest carry various unknown K-loci (KL115, KL128, KLI52, KL161 and KLI63). We also found that two isolates possess unknown loci for the lipopolysaccharide O-antigen (O1/O2v1 type OL104 and unknown O1). The rest possess known O1 and O3 serotypes. From MLST, we found four novel sequence types (STs), carrying novel alleles for the housekeeping genes glyceraldehyde-6-phosphate dehydrogenase A (gapA), glucose-6-phosphate isomerase (pgi), and RNA polymerase subunit beta (rpoB). Our AMR analysis revealed that all the isolates are resistant to ampicillin and ceftriaxone, with varied resistance to other antibiotics, but all carry genes for extended-spectrum beta-lactamases (ESBLs). Notably, one strain (RSM7756) possesses outstanding chromosomal and plasmid-encoded AMR to beta-lactams, cephalosporins, fluoroquinolones and methoprims. Conclusively, clinical samples from Mulago National Referral Hospital harbor novel STs and multidrug resistant K. oxytoca strains, with significant public health importance, which could have been underrated.

Clinical Pilot of Bacterial Transcriptional Profiling as a Combined Genotypic and Phenotypic Antimicrobial Susceptibility Test.

Antimicrobial resistance is a growing health threat, but standard methods for determining antibiotic susceptibility are slow and can delay optimal treatment, which is especially consequential in severe infections such as bacteremia. Novel approaches for rapid susceptibility profiling have emerged that characterize either bacterial response to antibiotics (phenotype) or detect specific resistance genes (genotype). GoPhAST-R is a novel assay, performed directly on positive blood cultures, that integrates rapid transcriptional response profiling with detection of key resistance gene transcripts, thereby providing simultaneous data on both phenotype and genotype. Here, we performed the first clinical pilot of GoPhAST-R on 42 positive blood cultures: 26 growing Escherichia coli, 15 growing Klebsiella pneumoniae, and 1 with both. An aliquot of each positive blood culture was exposed to 9 different antibiotics, lysed, then underwent rapid transcriptional profiling on the NanoString® platform; results were analyzed using an in-house susceptibility classification algorithm. GoPhAST-R achieved 95% overall agreement with standard antimicrobial susceptibility testing methods, with the highest agreement for beta-lactams (98%) and the lowest for fluoroquinolones (88%). Epidemic resistance genes including the extended spectrum beta-lactamase bla CTX-M-15 and the carbapenemase bla KPC were also detected within the population. This study demonstrates the clinical feasibility of using transcriptional response profiling for rapid resistance determination, although further validation with larger and more diverse bacterial populations will be essential in future work. GoPhAST-R represents a promising new approach for rapid and comprehensive antibiotic susceptibility testing in clinical settings.