Several efforts have been made to estimate the prevalence of different types of antibiotic resistance in different regions of Nigeria. The study investigated the prevalence of Klebsiella pneumoniae encoding genes for CTX-M, TEM, and SHV-1 extended-spectrum beta-lactamases (ESBL) enzymes isolated from urine samples of non-hospitalized patients with suspected UTI in Lagos State, Nigeria. A 4-month retrospective study, spanning from May 2023 to August 2023, was conducted. K. pneumoniae was isolated from urine samples using standard microbiological methods. The modified Kirby-Bauer disc diffusion method was used to test for antibiotic susceptibility, and Clinical and Laboratory Standard Institute (CLSI) guidelines were followed for interpretation. The double-disk synergy method was used to confirm the phenotypic identity of ESBL producers, and the results were interpreted in accordance with CLSI guidelines. The phenotypic method was utilized for ESBL screening, employing the standard disk diffusion method. The CTX-M ESBL gene, TEM gene, and SHV gene were found using multiplex PCR. Results revealed that 41 K. pneumoniae isolates were resistant to third-generation Cephalosporins; the isolates showed resistance to ceftazidime in 100% of cases and ceftriaxone in 80.49% of cases respectively. It was determined that 8 (19.51%) of the isolates produced ESBL. Among Klebsiella isolates, the frequencies of the SHV, TEM, and CTX-M genes were 31 (75.61%), 4 (9.76%), and 10 (24.39%), in that order. Four isolates (9.67%) had the SHV, TEM, and CTX-M genes, while eight (19.51%) of the isolates possessed both the SHV and CTX-M genes. This investigation demonstrates high frequency, wide range of patterns and coexistence of ESBL genes in K. pneumoniae isolates from outpatient UTI patients. Although several phenotypic tests have been used for ESBL detection, testing directly for the presence of ESBL genes is always more accurate. The majority of the isolates of Klebsiella pneumoniae ESBL producers had the SHV gene identified.

Flomoxef (FMX) may be a potential alternative to carbapenems for dogs infected with Enterobacterales producing extended-spectrum β-lactamase (ESBL-E). However, the appropriate dosage of FMX in dogs with ESBL-E infections has yet to be established. This study was carried out to establish appropriate treatment regimens for FMX against ESBL-E infections in dogs by a pharmacokinetics–pharmacodynamics (PK–PD) approach. Five dogs received an intravenous bolus dose of FMX (40 mg/kg). Serum FMX concentrations were evaluated using high-performance liquid chromatography-tandem mass spectrometry, and PK indices were determined based on non-compartmental model. The cumulative fraction of response (CFR) was calculated based on the distribution of minimum inhibitory concentrations among wild-type ESBL-E from companion animals. As the results, the dosage regimens of 40 mg/kg q8h and q6h were estimated to achieve a CFR of >90% for wild-type isolates of ESBL-producing Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis for dogs. In contrast, all regimens exhibited a CFR of <80% for ESBL-producing Enterobacter cloacae. Our results indicated that dosage regimens of 40 mg/kg FMX q8h and q6h can be a non-carbapenem treatment for dogs infected with ESBL-producing isolates of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, but not for those infected with ESBL-producing Enterobacter cloacae.

Klebsiella pneumoniae (Kp) has gained prominence in the last two decades due to its global spread as a multi-drug resistant (MDR) pathogen. Further, Carbapenem-Resistant Kp are emerging at an alarming rate. The objective of this study was (1) to evaluate the prevalence of β-lactamases, especially carbapenemases in Kp isolates from India, (2) determine the most prevalent sequence type (ST) & plasmids, and their association with β-lactamases. Clinical samples of K. pneumoniae (n=65) were collected from various pathology lab, drug susceptibility and minimum inhibitory concentrations (MIC) were detected. Whole genome sequencing (WGS) was done for (n=22) resistant isolates and WGS analysis was performed using various bioinformatics tools. Additional Indian MDR Kp genomes (n=187) were retrieved using Pathosystems Resource Integration Center (PATRIC) database. Detection of β-lactamase genes, location, plasmid replicons, and ST type of genomes were carried out using CARD, mlplasmids, PlasmidFinder, and PubMLST respectively. All data were analyzed and summarized using iTOL tool. ST231 was highest, followed by ST147, ST2096 & ST14 among Indian isolates. blaAmpH was detected as the most prevalent gene followed by blaCTX-M-15, blaTEM-1. Among carbapenemase genes, blaOXA-232 was prevalent and associated with ST231, ST2096 and ST14, which was followed by blaNDM-5 which was observed to prevalent in ST147, ST395 &ST437. ST231 genomes were most commonly found to carry Col440I and ColKP3 plasmids. ST16 carried mainly ColKP3, and Col (BS512) was abundantly present in ST147 genomes. One Kp isolate with novel MLST profile was identified, which carried blaCTX-M-15, blaOXA-1 and blaTEM-1. ST16 &ST14 from this study, which is mostly dual producer of carbapenem and ESBL genes, could be emerging high-risk clones in India.

Beta-lactam resistant bacteria, commonly resident in tertiary hospitals, have emerged as a worldwide health problem because of ready-to-eat vegetable intake. We aimed to characterize the genes providing resistance to beta-lactam antibiotics in Enterobacteriaceae, isolated from five commercial salad brands for human consumption in Mexico City. 25 samples were collected, grow in blood agar plates, the bacteria were biochemistry identified and antimicrobial susceptibility testing was done, the carried family genes were identified by endpoint PCR and the specific genes were confirmed with WGS by NGS. 12 positive cultures were identified and their microbiological distribution was as follows, 8.3% for Enterobacter aerogene (n=1), 8.3% for Serratia fonricola (n=1), 16.7% for Serratia marcesens (n=2), 16.7% for Klebsiella pneumoniae (n=2), and 50% (n=6) for Enterobacter cloacae. The endpoint PCR results showed 11 colonies positive for blaBIL (91.7%), 11 for blaSHV (91.7%), 11 for blaCTX (97.7%), 12 for blaDHA (100%),4 for blaVIM (33.3%), 2 for blaOXA (16.7%), 2 for blaIMP (16.7%), 1 for blaKPC (8.3%) and 1 for blaTEM (8.3%) gene, all samples were negative blaROB, blaCMY, blaP, blaCFX and blaLAP gene. The sequencing analysis revels a specific genotypes for Enterobacter cloacae (blaSHV-12, blaCTX-M-15, blaDHA-1, blaKPC-2); Serratia marcescens (blaSHV-1, blaCTX-M-3, blaDHA-1, blaVIM-2); Klebsiella pneumoniae (blaSHV-12, blaCTX-M-15, blaDHA-1); Serratia fonticola (blaSHV-12, blaVIM-1, blaDHA-1) and Enterobacter aerogene (blaSHV-1, blaCTX-M-1, blaDHA-1, blaVIM-2, blaOXA-9). Our results indicate that beta-lactam resistant bacteria have acquired integrons with a different number of genes that providing panresistance to beta-lactam antibiotics, including penicillins, oxacillins, cefalosporins, monobactams, carbapenems and imipenems.

This review aimed at defining and classifying extended spectrum β-lactamases, ESBLs and carbapenemases, summarizing the different phenotypic methods used to detect production of these enzymes in clinically significant gram negative bacteria and also describing the methods that discourse challenges mostly encountered during detection of these enzymes in microbiology laboratories with the purpose of formulating recommendations on best practice to screen for these enzymes. We conclude that the modified double disk synergy, MDDS is not only suitable for the confirmation of ESBL production after screening isolates with the cephalosporin/clavulanate combination disc diffusion or broth micro-dilution methods but also distinguishes ESBL production and over-expression of AmpC-derepressed mutants and as well serves as an indicator for AmpC screening. Furthermore, we suggest cefotaxime, ceftazidime and cefpodoxime (for testing using a single drug) as indicator antibiotics of choice for ESBL detection. The MDDS and cefoxitin/AmpC inhibitor combination disc method, using cloxacillin and phenylboronic acid can be used as screening tests for AmpC production and either the AmpC disc test, the disc approximation test or the modified three dimensional extract test as confirmatory tests for AmpC production. We also suggest that confirmation of carbapenemase production be done with the modified hodge test, using Klebsiella pneumoniae ATCC 700603 as the indicator organism or the modified carbapenem inactivation method. However, to differentiate between the different classes of carbapenemases, boronic acid and EDTA based methods (double-disk synergy tests and combined-disk tests) using imipenem, meropenem and ertapenem, in combination with 3-aminophenylboronic acid and ethylene diamine tetra acetic acid be used.

Metallo-β-lactamases (MBLs) are a group of Zn(II)-dependent enzymes that pose a major threat to global health. They are linked to an increasing number of multi-drug resistant bacterial pathogens, but no clinically useful inhibitor is yet available. Since β-lactam antibiotics, which are inactivated by MBLs, constitute ~65% of all antibiotics used to treat infections, the search for clinically relevant MBL inhibitors is urgent. Here, derivatives of a 2-amino-1-benzyl-4,5-diphenyl-1H-pyrrole-3-carbonitrile (1a) were synthesised and their inhibitory effects assessed against representatives of each of the three subgroups of MBLs (B1, B2, B3). Several compounds are potent inhibitors of each MBL tested, making them excellent candidates for the development of broad-spectrum drug leads. In particular, compound 5f is highly potent across the MBL subfamilies, with Ki values in the low µM range. Furthermore, this compound also dis-plays synergy in combination with antibiotics such as penicillin G, cefuroxime or meropenem. This molecule thus represents one of the most promising compounds developed yet to combat MBLs.

Active research of metal-containing compounds and enzymes as effective antifungal agents is currently noted. The interest in metals is due to the wide variety of ligands that can be used for metals, including chemically synthesized and naturally obtained variants as a result of the so-called "green synthesis". The main mechanism of antifungal action of metals is the triggering of generation and accumulation of reactive oxygen species (ROS). Further action of ROS on various biomolecules is nonspecific. This review highlights various hydrolytic enzymes (glucanases and proteases) that affect the structural elements of fungal cells (cell walls, membranes), fungal quorum sensing molecules, fungal own protective agents (mycotoxins and antibiotics), proteins responsible for the adhesion and formation of stable highly concentrated populations in the form of biofilms. A wide range of the substrates for enzymes allows the use of various mechanisms of their antifungal actions. The prospects of combining two different types of antifungal agents (metals and enzymes) for mycelial fungi and yeast cells are discussed in this review. Special attention is paid to the possible influence of metals on activity of the enzymes and the possible effects of proteins on antifungal activity of metal-containing compounds.