Extended-spectrum Β-lactamase Research Articles

Antimicrobial Use Survey and Detection of ESBL-Escherichia coli in Commercial and Medium-/Small-Scale Poultry Farms in Selected Districts of Zambia.

Antimicrobial resistance (AMR) among Escherichia coli from food animals is a rising problem, and heavy antimicrobial use in poultry is a contributing factor. In Zambia, studies linking poultry-associated AMR and antibiotic use (AMU) are rare. This study aimed to investigate commercial and medium-/small-scale poultry farmers' usage of antimicrobials based on a questionnaire survey in ten districts of Zambia. In addition, the study characterized extended-spectrum β-lactamase (ESBL)-producing E. coli isolates obtained from poultry in the same districts. Data regarding knowledge and usage of antimicrobials were collected from commercial and medium-/small-scale poultry farmers using a pre-tested structured questionnaire. At the same time, cloacal samples were collected and analyzed. One hundred and fifty E. coli isolates were tested for antimicrobial susceptibility using eight antibiotic classes. The isolates were further screened for ESBL production by streaking them on cefotaxime (CTX)-supplemented MacConkey agar, then subjecting them to sequencing on a NextSeq. The questionnaire survey showed that more medium-/small-scale than commercial poultry farmers used antimicrobials (OR = 7.70, 95% CI = 2.88-20.61) but less prescriptions (OR = 0.02, 95% CI = 0.00-0.08). Susceptibility testing revealed that resistance was highest to ampicillin (128/148, 86.5%) and tetracycline (101/136, 74.3%) and that the prevalence of multidrug resistance (MDR) (28/30, 93.3%) was high. Whole-genome sequencing (WGS) of eight (8/30, 26.7%) isolates with CTX Minimum Inhibitory Concentration (MIC) ≥ 4 µg/mL revealed the presence of ESBL-encoding genes blaCTX-M-14, blaCTX-M-55, and blaTEM. WGS also detected other AMR genes for quinolones, aminoglycosides, phenicols, tetracycline, macrolides, and folate-pathway antagonists. Altogether, the questionnaire survey results showed a higher proportion of AMU and lower prescription usage among medium-/small-scale farmers. In addition, our results emphasize the circulation of ESBL-producing E. coli strains with associated MDR. It is critical to educate farmers about AMR risks and to encourage responsible usage of antimicrobials. Furthermore, there is a need to strengthen regulations limiting access to antimicrobials. Finally, there is a need to establish a one health system to guide public health response.

Cefepime/Enmetazobactam: First Approval.

Cefepime/enmetazobactam (EXBLIFEP®), an intravenous (IV) antibacterial fixed-dose combination of a 4th generation cephalosporin and an extended-spectrum β-lactamase (ESBL) inhibitor, is being developed by Allecra Therapeutics and ADVANZ PHARMA for the treatment of infections caused by multi-drug-resistant (MDR) Gram-negative bacteria. In February 2024, cefepime/enmetazobactam was approved in the USA for use in adults with complicated urinary tract infections (cUTI) including pyelonephritis, caused by susceptible strains of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, and Enterobacter cloacae complex. In March 2024, cefepime/enmetazobactam was approved in the EU for use in adults for the treatment of cUTI, including pyelonephritis, and hospital-acquired pneumonia, including ventilator associated pneumonia, and the treatment of patients with bacteraemia occurring in association with or suspected to be associated with any of these infections. This article summarizes the milestones in the development of cefepime/enmetazobactam leading to this first approval for the treatment of adults with infections caused by MDR Gram-negative bacteria.

Epidemiological Study of Pathogens in Spontaneous Bacterial Peritonitis in 2017-2024-A Preliminary Report of the University Hospital in South-Eastern Poland.

Spontaneous Bacterial Peritonitis (SBP) is a serious complication and a common cause of death in patients with liver cirrhosis. Between January 2017 and March 2024, a retrospective study was conducted involving 302 patients (>18 years old) with ascites treated at a tertiary referral center in south-eastern Poland. Microbiological analysis of the ascitic fluids was performed in all patients. The presence of microorganisms was found in samples from 17 patients, and 21 pathogens were isolated, including 15 Gram-positive bacteria and 6 Gram-negative bacteria. Staphylococcus epidermidis, MRCNS (methicillin-resistant coagulase-negative staphylococci, resistant to all beta-lactam antibiotics: penicillins, penicillins with beta-lactamase inhibitor, cephalosporins and carbapenems) was the main pathogen detected (19.05%, 4/21), followed by Enterococcus faecalis (9.52%, 2/21), Enterococcus faecium (9.52%, 2/21), Staphylococcus haemolyticus, MRCNS (4.76%, 1/21), Streptococcus mitis (9.52%, 2/21), Streptococcus parasanguinis (9.52%, 2/21), Micrococcus luteus (4.76%, 1/21) and Bacillus spp. (4.76%, 1/21). The following Gram-negative bacteria were also found in the specimens examined: Escherichia coli, ESBL (extended-spectrum β-lactamase producing E. coli) (4.76%, 1/21), Escherichia coli (4.76%, 1/21), Pseudomonas aeruginosa (4.76%, 1/21), Klebsiella oxytoca (9.52%, 2/21) and Sphingomonas paucimobilis (4.76%, 1/21). Gram-positive bacteria caused nosocomial infections in nine patients with SBP, Gram-negative bacteria caused nosocomial infections in two patients. In six patients with SBP, community-acquired infections caused by Gram-negative bacteria were found in three cases, Gram-positive bacteria in two cases, and in one case, community-acquired infection was caused by mixed Gram-positive and Gram-negative. Bacteria isolated from patients with hospital-acquired SBP showed higher drug resistance than those found in patients with non-hospital SBP. Bacterial infections in cirrhotic patients with complications may be responsible for their deteriorating health. Prompt intervention is critical to reducing mortality.

Multidrug-Resistant Bacteria in Surgical Intensive Care Units: Antibiotic Susceptibility and β-Lactamase Characterization.

Multidrug-resistant (MDR) bacteria of the utmost importance are extended-spectrum β-lactamase (ESBL) and carbapenemase-producing Enterobacterales (CRE), carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp. (VRE). In this study, an evaluation of MDR bacteria in surgical intensive care units in a tertiary referral hospital was conducted. The study aimed to characterize β-lactamases and other resistance traits of Gram-negative bacteria isolated in surgical intensive care units (ICUs). Disk diffusion and the broth dilution method were used for antibiotic susceptibility testing, whereas ESBL screening was performed through a double disk synergy test and an inhibitor-based test with clavulanic acid. A total of 119 MDR bacterial isolates were analysed. ESBL production was observed in half of the Proteus mirabilis, 90% of the Klebsiella pneumoniae and all of the Enterobacter cloacae and Escherichia coli isolates. OXA-48 carbapenemase, carried by the L plasmid, was detected in 34 K. pneumoniae and one E. coli and Enterobacter cloacae complex isolates, whereas NDM occurred sporadically and was identified in three K. pneumoniae isolates. OXA-48 positive isolates coharboured ESBLs belonging to the CTX-M family in all but one isolate. OXA-23 carbapenemase was confirmed in all A. baumannii isolates. The findings of this study provide valuable insight of resistance determinants of Enterobacterales and A. baumannii which will enhance surveillance and intervention strategies that are necessary to curb the ever-growing carbapenem resistance rates.

Chemical Profile with Antibacterial and Modulatory Activity of Extracts from the Stem Bark of Cnidoscolus quercifolius Pohl.

Objective: The present study aimed to investigate the chemical profile and evaluate the antibacterial and antibiotic-modulating activity of the methanolic extract and ethyl acetate of the stem bark of C. quercifolius against standard and multiresistant strains. Methods: The Minimum Inhibitory Concentration was determined by the microdilution method, and the modulating potential of the extracts on aminoglycoside and β-lactam antibiotics was evaluated. Results: The classes of secondary metabolites identified from qualitative chemical prospecting were flavones, flavonols, xanthones, flavonones, flavonols, catechins and leucoanthocyanidins. The assays showed inhibition only for Klebsiella pneumoniae-producing extended-spectrum β- lactamase, Klebsiella pneumoniae carbapenemase and Escherichia coli ATCC 25922 with MICs of 256, 512 and 512 μg/mL, respectively. The extracts, when associated with gentamicin and amoxicillin, showed synergism against all standard and multiresistant strains, with the exception of Klebsiella pneumoniae carbapenemase and Klebsiella pneumoniae producing extendedspectrum β-lactamase, respectively. When combined with amikacin, they also demonstrated synergism against multidrug-resistant strains; however, only the ethyl acetate extract had a synergistic effect against E. coli ATCC 25922. The association of penicillin with methanolic extract showed synergism only for Klebsiella pneumoniae producing extended-spectrum β-lactamase and S. aureus ATCC 29213, while the ethyl acetate extracts demonstrated synergism against S. aureus and Klebsiella pneumoniae producing extended-spectrum β-lactamase. Conclusion: It was found that C. quercifolius extracts have antibacterial potential against gramnegative bacteria. However, the need for additional research using specific methods against bacteria carrying different resistance mechanisms, especially gram-positive ones, is highlighted, with the aim of elucidating their mechanism of action. conclusion: The species was found to have substances with potential against Gram-negative bacteria. However, the need for additional research using specific methods against bacteria carrying different resistance mechanisms, especially Gram-positive ones, is highlighted, with the aim of elucidating their mechanism of action.

Genomic and Functional Characterization of CTX-M-15-Producing Klebsiella pneumoniae ST307 Isolated from Imported Leopard Tortoises in Germany

The Klebsiella pneumoniae ST307 clone, identified in the mid-1990s, has emerged as a global antimicrobial-resistant (AMR) high-risk clone, significantly contributing to the global health challenge also posed by other AMR K. pneumoniae lineages. The acquisition of a blaCTX-M-15-carrying plasmid has facilitated its widespread dissemination. At Europe’s major transport hub for the movement of live animals, Frankfurt Airport, a shipment of 20 live leopard tortoises was sampled during German border control in 2014. Phylogenetic analysis (MLST) identified a K. pneumoniae ST307 strain, prompting further investigation. Our analysis revealed the presence of a ~193 kb plasmid carrying a broad range of AMR genes, including blaCTX-M-15, blaTEM-1B, blaOXA-1, aac(3)-IIa, aac(6′)-Ib-cr, aph(3″)-Ib, aph(6)-Id, and qnrB1. Additionally, mutations in the quinolone resistance-determining region in gyrA (S83I) and parC (S80I) were detected. Phenotypic testing demonstrated resistance of the isolate to the most common antimicrobials used in both human and veterinary medicine; exceptions included carbapenems and newer β-lactamase inhibitor combinations. Because the role of imported exotic animals in the dissemination of AMR genes is largely deficient, the present study fills yet missing mosaic pieces in the complete picture of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales.

Genomic analysis of the first multidrug-resistant ESBL-producing high-risk clonal lineage Klebsiella pneumoniae ST147 isolated from a cat with urinary tract infection.

Urinary tract infections (UTIs) are pervasive in human and veterinary medicine, notably affecting companion animals. These infections frequently lead to the prescription of antibiotics, contributing to the rise of antimicrobial-resistant bacteria. This escalating concern is underscored by the emergence of a previously undocumented case: a high-risk clone, broad-spectrum cephalosporin-resistant K. pneumoniae ST147 strain, denoted USP-275675, isolated from a cat with UTI. Characterized by a multidrug-resistant (MDR) profile, whole genome sequencing exposed several antimicrobial-resistance genes, notably blaCTX-M-15, blaTEM-1B, blaSHV-11, and blaOXA-1. ST147, recognized as a high-risk clone, has historically disseminated globally and is frequently associated with carbapenemases and extended-spectrum β-lactamases. Notably, the core-genome phylogeny of K. pneumoniae ST147 strains isolated from urine samples revealed a unique aspect of the USP-276575 strain. Unlike its counterparts, it did not cluster with other isolates. However, a broader examination incorporating strains from both human and animal sources unveiled a connection between USP-276575 and a Portuguese strain from chicken meat. Both were part of a larger cluster of ST147 strains spanning various geographic locations and sample types, sharing commonalities such as IncFIB or IncR plasmids. This elucidates the MDR signature inherent in widespread K. pneumoniae ST147 strains carrying these plasmids, highlighting their pivotal role in disseminating antimicrobial resistance (AMR). Finally, discovering the high-risk clone K. pneumoniae ST147 in a domestic feline with a UTI in Brazil highlights the urgent need for thorough AMR surveillance through a One Health approach.

Epidemiological Characteristics of Shiga Toxin-Producing Escherichia coli Responsible for Infections in the Polish Pediatric Population.

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in children and the elderly. Stool samples were collected from 180 children hospitalized in five pediatric centers in Poland in 2018-2022. Direct stx1/stx2 gene detection by PCR in feces and E. coli isolates was performed. Antibiotic susceptibility was tested according to EUCAST v.12. Randomly selected isolates were serotyped with O157 antiserum and genotyped by pulsed-field gel electrophoresis (PFGE). A total of 44 E. coli isolates were confirmed as STEC by PCR. Among them, 84.4% were positive for stx2, and equally 6,8% for only stx1 and both stx1 and stx2 genes. The stx1 gene was also found in one Citrobacter freundii isolate. E. coli serotype O157 was present in 97.6% of the isolates. STEC infections most often occurred between June-October with a peak in July and August (51%). The highest, 77.8% of STEC isolates were found in the 1-5 years old group. No extended-spectrum β-lactamases (ESBL) were found. Resistance only to amoxicillin/clavulanic acid (24.4%), piperacillin/tazobactam (3%), cefotaxime (6%), gentamicin (6%), ciprofloxacin (3%), azithromycin (3%), trimethoprim/sulfamethoxazole (24,2%) was detected. PFGE analysis showed 18 PFGE types with no clonal distribution. Eight isolates with A, B, and C PFGE types showed genetic relatedness in the type with no detection of transmission way of distribution. STEC strains pose a serious threat to human health, therefore demographic and epidemiological characteristics are crucial for their surveillance.

Surveillance of Enterobacteriaceae from Diabetic Foot Infections in a Tunisian Hospital: Detection of E. coli-ST131-blaCTX-M-15 and K. pneumoniae-ST1-blaNDM-1 Strains.

The study determined the prevalence, antimicrobial resistant (AMR) determinants, and genetic characteristics of Escherichia coli and Klebsiella pneumoniae isolates from patients with diabetic foot infection (DFI) in a Tunisian hospital. A total of 26 Escherichia spp. and Klebsiella spp. isolates were recovered and identified by MALDI-TOF-MS. Antimicrobial susceptibility testing, the detection of AMR determinants and Shiga-like toxin genes, phylogenetic grouping, and molecular typing were performed. Twelve E. coli, 10 K. pneumoniae, 3 K. oxytoca, and 1 E. hermanii were isolated. A multidrug-resistant phenotype was detected in 65.4% of the isolates. About 30.8% of isolates were extended-spectrum β-lactamase (ESBL) producers and mainly carried blaCTX-M-15 and blaCTX-M-14 genes. One blaNDM-1-producing K. pneumoniae-ST1 strain was identified. Class 1 integrons were detected in 11 isolates and 5 gene cassette arrangements were noted: dfrA1+aadA1 (n = 1), dfrA12+aadA2 (n = 3), and dfrA17+aadA5 (n = 1). Other non-β-lactam resistance genes detected were as follows (number of isolates): aac(3')-II (3), aac(6')-Ib-cr(8), qnrB (2), qnrS (4), cmlA (2), floR (4), sul1 (11), sul2 (11), and sul3 (2). The phylogroup B1 was the most frequent (41.7%) among E. coli, and two ESBL-producing isolates corresponded to the ST131-B2 lineage. The ESBL- and carbapenemase-producing Enterobacteriaceae in DFIs are described for the first time in Tunisia.

Large hospital outbreak caused by OXA-244-producing Escherichia coli sequence type 38, Poland, 2023.

In February 2023, Escherichia coli sequence type (ST) 38 producing oxacillinase 244 (OXA-244-Ec ST38) was detected from three patients in a hospital in western Poland. Overall, OXA-244-Ec ST38 was detected from 38 colonised patients in 13 wards between February and June 2023. The outbreak was investigated on site by an infection control team, and the bacterial isolates were characterised microbiologically and by whole genome sequencing. We could not identify the primary source of the outbreak or reconstruct the transmission sequence. In some of the 13 affected wards or their groups linked by the patients' movement, local outbreaks occurred. The tested outbreak isolates were resistant to β-lactams (penicillins, cephalosporins, aztreonam and ertapenem) and to trimethoprim-sulfamethoxazole. Consistently, apart from bla OXA-244, all isolates contained also the bla CMY-2 and bla CTX-M-14 genes, coding for an AmpC-like cephalosporinase and extended-spectrum β-lactamase, respectively, and genes conferring resistance to trimethoprim-sulfamethoxazole, sul2 and dfrA1. Genomes of the isolates formed a tight cluster, not of the major recent European Cluster A but of the older Cluster B, with related isolates identified in Germany. This outbreak clearly demonstrates that OXA-244-Ec ST38 has a potential to cause hospital outbreaks which are difficult to detect, investigate and control.

Clinical Analysis of Bacterial Infection Characteristics in Lymphoma Patients with High-dose Chemotherapy Combined with Autologous Hematopoietic Stem Cell Transplantation-A Single-Centered Retrospective Study.

High-dose chemotherapy combined with autologous hematopoietic stem cell transplantation (HDT/AHSCT) is used to treat lymphoma. Although AHSCT has made considerable strides and become safer, HDT-AHSCT infection continues to be a leading cause of morbidity and mortality associated with transplantation. To characterise pathogenic bacterial infections in HDT/AHSCT-treated lymphoma patients. The prevalence of pathogenic microorganisms and the timing of foci after transplantation, along with bloodstream infection (BSI) risk factors, can help determine the need for empirical antibiotics after AHSCT. We retrospectively analyzed 133 lymphoma patients treated by HDT/AHSCT from April 2017 to October 2021 at Peking University International Hospital, Beijing, China. We analyzed their clinical characteristics, microbiological distribution characteristics, and BSI risk factors in detail. In order, intestinal infection (56 cases), BSI (17 cases), pulmonary (12 cases), upper respiratory tract (5 cases), and perianal (4 cases) were the most common locations of infection after HDT/AHSCT. The infection sites yielded 92 putative pathogenic pathogens, with bacteria predominating (61.96%), fungi (28.26%), viruses (5.43%), and mycoplasma (4.35%). Gram-negative bacteria (GNB) strains outnumbered gram-positive bacteria (GPB) strains (73.68%). Two strains of Escherichia coli produced extended-spectrum β-lactamase (ESBL) and one strain of carbapenem-resistant enterobacteriaceae (CRE). Methicillin-resistant Staphylococcus epidermidis (MRSE) had one strain. BSI was caused by Escherichia coli (82.35%), Intestinal mucositis (23.52%), and catheter-associated infections (11.76%). Age, CD34, pretreatment regimen, antibiotic regimen, and past chemotherapeutic agent lung damage were BSI risk variables in univariate analysis. CD34 and past chemotherapeutic drug lung damage were the primary causes of BSI after HDT/AHSCT for lymphoma. High-dose chemotherapy combined with autologous hematopoietic stem cell transplantation (HDT/AHSCT) is used to treat lymphoma. Although AHSCT has made considerable strides and become safer, HDT-AHSCT infection continues to be a leading cause of morbidity and mortality associated with transplantation.

Homology of Escherichia coli isolated from urine and vagina and their antimicrobial susceptibility in postmenopausal women with recurrent cystitis

Uropathogenic Escherichia coli (UPEC) is a typical cystitis-causing organism that can migrate from the vagina to the bladder and cause recurrent cystitis (RC). Few reports have compared the characteristics of urinary and vaginal UPEC in patients with RC. We carried out molecular biological analyses of Escherichia coli (E. coli) strains and their antimicrobial susceptibility to assess the association between urinary and vaginally UPEC. We included E. coli isolated from urinary and vaginal samples at the onset of cystitis in postmenopausal women with RC between 2014 and 2019 in our hospital. Pulsed-field gel electrophoresis (PFGE) was performed using a restriction enzyme (Xba I). These sequences were compared with 17 antimicrobial susceptibilities determined by a micro-liquid dilution method. Multilocus sequence typing (MLST) and classification of extended-spectrum β-lactamase (ESBL) genotypes by multiplex polymerase chain reaction (PCR) were performed on ESBL-producing E. coli. We analyzed 14 specimens (each seven urine and vaginal) from seven patients in total. On PFGE, the similarity of urinary and vaginal E. coli per patient ranged from 89.5 to 100 %, including four patients with 100 % matches. MLST demonstrated that 29 % (4/14 specimens) were strain sequence type 131. Two specimens contained ESBL-producing strains and identified the CTX-M-27 genotype for each specimen. For each patient, antimicrobial susceptibilities between urinary and vaginal E. coli were mostly identical. Thus, urinary- and vaginally-derived E. coli were identical in postmenopausal women with RC. Management targeting both urinary and vaginal UPEC is essential for RC, indicating the importance of a vagina-targeted approach.

Clinical Characteristics, Prognosis and Treatment of Bloodstream Infections with Enterobacter Cloacae Complex in a Chinese Tertiary Hospital: A Retrospective Study.

This research aimed to analyze the clinical characteristics, prognosis, and antimicrobial treatment of bloodstream infections (BSI) caused by Enterobacter cloacae complex (ECC). The clinical data of patients with bloodstream infections caused by Enterobacter cloacae complex from April 2017 to June 2023 were collected retrospectively. These data were then analyzed in subgroups based on the detection results of extended-spectrum β-lactamase (ESBL), 30-day mortality, and the type of antimicrobial agent used (β-lactam/β-lactamase inhibitor combinations (BLICs) or carbapenems). The proportion of ESBL-producing Enterobacter cloacae complex was 32.5% (37/114). Meanwhile, ICU admission, receiving surgical treatment within 3 months, and biliary tract infection were identified as risk factors for ESBL-producing ECC-BSI. Additionally, immunocompromised status and Sequential Organ Failure Assessment (SOFA) score ≥ 6.0 were identified as independent risk factors of 30-day mortality in patients with ECC-BSI (n = 108). Further analysis in BSI patients caused by non-ESBL-producing ECC revealed that patients treated with BLICs (n = 45) had lower SOFA scores and lower incidence of hypoproteinemia and sepsis compared with patients treated with carbapenems (n = 20). Moreover, in non-ESBL-producing ECC-BSI patients, the univariate Cox regression analysis indicated a significantly lower 30-day mortality rate in patients treated with BLICs compared to those treated with carbapenems (hazard ratios (HR) [95% CI] 0.190 [0.055-0.662], P = 0.009; adjusted HR [95% CI] 0.106 [0.013-0.863], P = 0.036). This study investigated the factors influencing the susceptibility to infection by ESBL-producing strains and risk factors for 30-day mortality in ECC-BSI patients. The results revealed that ESBL-negative ECC-BSI patients treated with BLICs exhibited significantly lower 30-day mortality compared to those treated with carbapenems. BLICs were found to be more effective in ECC-BSI patients with milder disease (ESBL-negative and SOFA ≤6.0).

Rapid screening of positive blood cultures for extended-spectrum β-lactamases and metallo-β-lactamases using a drug susceptibility testing microfluidic method

ObjectivesAn increasing number of drug-resistant bacteria have been identified recently. In particular, drug-resistant bacteria have been linked to unfavorable prognoses in patients with bacteremia, highlighting the need for rapid testing. Our previous studies have focused on the utility of a drug susceptibility testing microfluidic (DSTM) method using microfluidic channels. A system with this DSTM method for screening for β-lactamases can rapidly detect extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs). In this study, we have evaluated the clinical utility of pre-treatment for screening positive blood cultures using the DSTM method. MethodsA total of 178 positive blood cultures and five simulated samples of MBL-producing bacteria were prepared at Kochi University Hospital, Japan. The pretreatment consisted of a two-step centrifugation. The obtained sediments were screened with the DSTM method for the production of β-lactamase based on morphological changes in the bacteria after 3 h of incubation. ResultsThe pretreatment functioned properly for all samples. Of the 25 ESBL samples, 21 were positive for ESBLs. Four false-negative samples, all obtained from the same patient, contained CTX-M-2 enzyme-producing Proteus mirabilis and showed insusceptibility to an ESBL inhibitor. The simulated samples prepared for MBL screening were positive for MBLs. ConclusionsWhen combined with a method for rapidly identifying bacterial species, DSTM may enable patients with bloodstream infections to start receiving appropriate treatment within 4 h after positive blood cultures are screened.

A novel variant in Salmonella genomic island 1 of multidrug-resistant Salmonella enterica serovar Kentucky ST198.

Salmonella enterica serovar Kentucky ST198 is a major health threat due to its resistance to ciprofloxacin and several other drugs, including third-generation cephalosporins. Many drug-resistant genes have been identified in the Salmonella genomic island 1 variant K (SGI1-K). In this study, we investigated the antimicrobial resistance (AMR) profile and genotypic relatedness of two isolates of ciprofloxacin-resistant (CIPR) S. Kentucky ST198 from poultry in Northeastern Thailand. We successfully assembled the complete genomes of both isolates, namely SSSE-01 and SSSE-03, using hybrid de novo assembly of both short- and long-read sequence data. The complete genomes revealed their highly similar genomic structures and a novel variant of SGI1-K underlying multidrug-resistant (MDR) patterns, including the presence of blaTEM-1b, which confers resistance to beta-lactams, including cephalosporins and lnu(F) which confers resistance to lincomycin and other lincosamides. In addition, the chromosomal mutations in the quinolone resistance-determining region (QRDR) were found at positions 83 (Ser83Phe) and 87 (Asp87Asn) of GyrA and at positions 57 (Thr57Ser) and 80 (Ser80Ile) of ParC suggesting high resistance to ciprofloxacin. We also compared SSSE-01 and SSSE-03 with publicly available complete genome data and revealed significant variations in SGI1-K genetic structures and variable relationships to antibiotic resistance. In comparison to the other isolates, SGI1-K of SSSE-01 and SSSE-03 had a relatively large deletion in the backbone, spanning from S011 (traG∆) to S027 (resG), and the inversion of the IS26-S044∆-yidY segment. Their MDR region was characterized by the inversion of a large segment, including the mer operon and the relocation of IntI1 and several resistance genes downstream of the IS26-S044∆-yidY segment. These structural changes were likely mediated by the recombination of IS26. The findings broaden our understanding of the possible evolution pathway of SGI1-K in fostering drug resistance, which may provide opportunities to control these MDR strains.IMPORTANCEThe emergence of ciprofloxacin-resistant (CIPR) Salmonella Kentucky ST198 globally has raised significant concerns. This study focuses on two poultry isolates from Thailand, revealing a distinct Salmonella genomic island 1 variant K (SGI1-K) genetic structure. Remarkably, multiple antibiotic resistance genes (ARGs) were identified within the SGI1-K as well as other locations in the chromosome, but not in plasmids. Comparing the SGI1-K genetic structures among global and even within-country isolates unveiled substantial variations. Intriguingly, certain isolates lacked ARGs within the SGI1-K, while others had ARGs relocated outside. The presence of chromosomal extended-spectrum β-lactamase (ESBL) genes and lincosamide resistance, lnu(F), gene, could potentially inform the choices of the treatment of CIPRS. Kentucky ST198 infections in humans. This study highlights the importance of understanding the diverse genetic structures of SGI1-K and emphasizes the role of animals and humans in the emergence of antimicrobial resistance.

Simultaneous detection of phylogroups and ESBL genes in E. coli using Multiplex PCR

Background: Escherichia coli (E. coli) strains harbor various allelic versions of beta lactamase genes and their identification using conventional phenotypic tests is a tedious and time consuming task. In the present study, multiplex PCR is performed for the simulatanoues detection of E. coli phylogroups and extended-spectrum β-lactamase- (ESBL) genes.Methods: A total of 128 E. coli isolates from urine samples were screened for antibiotic resistance and expression of ESBL activity using phenotypic and genotypic methods. Uniplex and multiplex PCRs were used to detect E. coli phylogroup detrminants and blaCTX-M-15, blaOXA-1 and TEM1 genes. Chi Square test of independence was employed for evaluating significant levels at P value < 0.05. Results: Phylogroup B2 was detected as the predominant group (36%) followed by group D (30%), A (25%) and B1 (9%). The highest resistance was seen against nalidixic acid (100%) and the lowest against amoxicillin-clavulanic acid (55%). Significant P values were observed for resistance against cefotaxime and cefepime in the phylogroup B2 while resistance against cefoxitin, sulfamethoxazole and fosfomycin was significantly associated with group D. Combination disc diffusion test (CDDT) showed ESBL activity in 42% E. coli isolates. A significant association of blaCTX-M-15 gene was observed for phylogroup B2 (P = 0.007). Moreover, a combination genotype of blaCTX-M-15 and TEM1 was also found statistically prevalent in phylogroup B2 (P = 0.006).Conclusion: The study highlights the alarming rise in antibiotic resistance and delineates B2 a predominant phylogoup with a high prevalence of blaCTX-M-15 and TEM1 genes in urinary E. coli isolates.Keywords: UTI; E. Coli; Phylogenetic groups; ESBL genes; Multiplex PCR

Microbiology of Klebsiella with extended-spectrum β-lactamases production

Extended-spectrum β-lactamases (ESBL) producing Klebsiella represents one of the greatest challenges in therapeutic management of the patients. Hence, the objective was to determine ESBL producing Klebsiella species and its molecular characterization in clinical samples of tertiary-care hospital. Klebsiella isolated from various samples were included and by using disc diffusion method ESBL detection amongst the Klebsiella isolates along with molecular detection of blaTEM, blaSHV, blaCTX-M genes which are associated with ESBL production was done. Results revealed that out of 3194 samples, 200 Klebsiella species were isolated. The ratio of Klebsiella species isolated from inpatient and outpatient departments was 75.5% and 24.5% respectively. The maximum isolates were obtained from men consisting of 57.50% and aged between 31-40 years with 26.50%. Majorly Klebsiella species were isolated from sputum including 30.5%, followed by urine consisting of 28% and pus samples with 19.5%. From the 200 isolates, 197 were Klebsiella pneumonia and 32.5% were ESBL producers with majorly having the blaTEM gene incorporated. Being Multidrug and Pan-drug resistant, Klebsiella with ESBL strains are a threat to mankind. This can be overcome by adhering to strict hospital policies to avoid irrational use of antibiotics, strictly following institutional and National antibiotic policies and by prescribing antibiotics according to the culture and sensitivity reports.

Regional variations in antimicrobial susceptibility of community-acquired uropathogenic Escherichia coli in India: Findings of a multicentric study highlighting the importance of local antibiograms

ObjectivesEvidence-based prescribing is essential to optimize patient outcomes in cystitis. This requires knowledge of local antibiotic resistance rates. Diagnostic and Antimicrobial Stewardship (DASH) to Protect Antibiotics (https://dashuti.com/) is a multicentric mentorship program guiding centers in preparing, analyzing and disseminating local antibiograms to promote antimicrobial stewardship in community urinary tract infection. Here, we mapped the susceptibility profile of Escherichia coli from 22 Indian centers. MethodsThese centers spanned 10 Indian states and three union territories. Antibiograms for urinary E. coli from the outpatient departments were collated. Standardization was achieved by regional online training; anomalies were resolved via consultation with study experts. Data were collated and analyzed. ResultsNationally, fosfomycin, with 94% susceptibility (inter-center range 83-97%), and nitrofurantoin, with 85% susceptibility (61-97%), retained the widest activity. The susceptibility rates were lower for co-trimoxazole (49%), fluoroquinolones (31%), and oral cephalosporins (26%). The rates for third- and fourth-generation cephalosporins were 46% and 52%, respectively, with 54% (33-58%) extended-spectrum β-lactamase prevalence. Piperacillin-tazobactam (81%), amikacin (88%), and meropenem (88%) retained better activity; however, one center in Delhi recorded only 42% meropenem susceptibility. Susceptibility rates were mostly higher in South, West, and Northeast India; centers in the heavily populated Gangetic plains, across north and northwest India, had greater resistance. These findings highlight the importance of local antibiograms in guiding appropriate antimicrobial choices. ConclusionsFosfomycin and nitrofurantoin are the preferred oral empirical choices for uncomplicated E. coli cystitis in India, although elevated resistance in some areas is concerning. Empiric use of fluoroquinolones and third-generation cephalosporins is discouraged, whereas piperacillin/tazobactam and aminoglycosides remain carbapenem-sparing parenteral agents.

Neonatal Sepsis Due to Multidrug-resistant Bacteria at a Tertiary Teaching Hospital in Ethiopia.

The burden of multidrug-resistant bacterial infections in low-income countries is alarming. This study aimed to identify the bacterial etiologies and antibiotic resistance patterns among neonates in Jimma, Ethiopia. An observational longitudinal study was conducted among 238 presumptive neonatal sepsis cases tested with blood and/or cerebrospinal fluid culture. The bacterial etiologies were confirmed using matrix-assisted laser desorption ionization-time of flight mass spectrometry. The antibiotic resistance patterns were determined using the automated disc diffusion method (Bio-Rad) and the results were interpreted based on the European Committee on Antimicrobial Susceptibility Testing 2021 breakpoints. Extended-spectrum β-lactamases were detected using a double disc synergy test and confirmed by Mast discs (Mast Diagnostica GmbH). A total of 152 pathogens were identified. Of these, Staphylococcus aureus (18.4%) was the predominant isolate followed by Klebsiella pneumoniae (15.1%) and Escherichia coli (10.5%). All the isolates exhibited a high rate of resistance to first- and second-line antibiotics ranging from 73.3% for gentamicin to 93.3% for ampicillin. Furthermore, 74.4% of the Gram-negative isolates were extended-spectrum β-lactamase producers and 57.1% of S. aureus strains were methicillin resistant. The case fatality rate was 10.1% and 66.7% of the deaths were attributable to infections by multidrug-resistant pathogens. The study revealed a high rate of infections with multidrug-resistant pathogens. This poses a significant challenge to the current global and national target to reduce neonatal mortality rates. To address these challenges, it is important to employ robust infection prevention practices and continuous antibiotic resistance testing to allow targeted therapy.

What Contributes to the Minimum Inhibitory Concentration? Beyond β-Lactamase Gene Detection in Klebsiella pneumoniae.

Klebsiella pneumoniae is capable of resistance to β-lactam antibiotics through expression of β-lactamases (both chromosomal and plasmid-encoded) and downregulation of outer membrane porins. However, the extent to which these mechanisms interplay in a resistant phenotype is not well understood. The purpose of this study was to determine the extent to which β-lactamases and outer membrane porins affected β-lactam resistance. Minimum inhibitory concentrations (MICs) to β-lactams and inhibitor combinations were determined by agar dilution or Etest. Outer membrane porin production was evaluated by Western blot of outer membrane fractions. β-lactamase carriage was determined by whole genome sequencing and expression evaluated by real-time reverse-transcription polymerase chain reaction. Plasmid-encoded β--lactamases were important for cefotaxime and ceftazidime resistance. Elevated expression of chromosomal SHV was important for ceftolozane-tazobactam resistance. Loss of outer membrane porins was predictive of meropenem resistance. Extended-spectrum β-lactamases and plasmid-encoded AmpCs (pAmpCs) in addition to porin loss were sufficient to confer resistance to the third-generation cephalosporins, piperacillin-tazobactam, ceftolozane-tazobactam, and meropenem. pAmpCs (CMY-2 and DHA) alone conferred resistance to piperacillin-tazobactam. Detection of a resistance gene by whole genome sequencing was not sufficient to predict resistance to all antibiotics tested. Some β-lactam resistance was dependent on the expression of both plasmid-encoded and chromosomal β-lactamases and loss of porins.