Extensive Drug Resistance Research Articles

Novel Variant of New Delhi Metallo-Beta-Lactamase (blaNDM-60) Discovered in a Clinical Strain of Escherichia coli from the United Arab Emirates: An Emerging Challenge in Antimicrobial Resistance

Background/Objectives: Carbapenem resistance poses a significant health threat. This study reports the first detection and characterization of a novel variant of New Delhi metallo-β-lactamase (blaNDM-60) in Escherichia coli from the United Arab Emirates (UAE), including its genetic context and relationship to global strains. Methods: NDM-60-producing E. coli was isolated from a rectal swab during routine screening. Characterization involved whole-genome sequencing, antimicrobial susceptibility testing, and comparative genomic analysis with 66 known NDM variants. Core genome analysis was performed against 42 global E. coli strains, including the single other reported NDM-60-positive isolate. Results: The strain demonstrated extensive drug resistance, including resistance to novel β-lactam/β-lactamase inhibitor combinations, notably taniborbactam. NDM-60 differs from the closely related NDM-5 by a single amino acid substitution (Asp202Asn) and two amino acid substitutions (Val88Leu and Met154Leu) compared to NDM-1. NDM-60 is located on a nonconjugative IncX3 plasmid. The strain belongs to sequence type 940 (ST940). Phylogenetic analysis revealed high diversity among the global ST940 strains, which carry a plethora of resistance genes and originated from humans, animals, and the environment from diverse geographic locations. Conclusions: NDM-60 emergence in the UAE represents a significant evolution in carbapenemase diversity. Its presence on a nonconjugative plasmid may limit spread; however, its extensive resistance profile is concerning. Further studies are needed to determine the prevalence, dissemination, and clinical impact of NDM-60. NDM evolution underscores the ongoing challenge in managing antimicrobial resistance and the critical importance of vigilant molecular surveillance. It also highlights the pressing demand to discover new antibiotics to fight resistant bacteria.

Role and mechanism of the outer membrane porin LamB in T-2 mycotoxin-mediated extensive drug resistance in Escherichia coli

The influence of mycotoxins in ecological niches shared with antibiotic-resistant bacteria (ARB) remains underexplored. This study examined the impact of T-2 mycotoxin on the evolution of antibiotic resistance in Escherichia coli, highlighting the role of specific porins. Our findings revealed that exposure to 10ng/mL of T-2 toxin induced multi-drug resistant (MDR) phenotypes in three E. coli. At 10-5ng/mL, T-2 toxin caused E. coli ATCC 25922 to develop stable resistance to 13 critical antibiotics, with minimum inhibitory concentrations (MICs) increasing 16- to several thousand-fold. This resistance was linked to the downregulation of the mal gene cluster. Notably, T-2 toxin reduced membrane permeability by downregulating lamB, facilitating its own entry and reducing the intracellular accumulation of both the toxin and antibiotics, thereby enhancing resistance development. LamB mediated the XDR phenotypes in E. coli, particularly by blocking last-resort antibiotics such as cephalosporins, carbapenems, tigecycline, and colistin, complicating treatment strategies. LamB demonstrated high binding affinities for T-2 toxin and various antibiotics, with specific binding sites identified for meropenem (Arg134), imipenem (Ser148, Arg170, Lys129), ceftazidime (Phe106, Lys129), and cefepime (Tyr66, Gln267, Lys269), exhibiting binding energies of -2.93, -2.58, -2.53, and -4.3, respectively. These findings suggest that even low levels of T-2 mycotoxin pose a substantial public health risk. They underscore the urgent need to address these contaminants and open new avenues for antibiotic resistance research.

Genomic Insights of Multidrug-Resistant Enterococcus faecalis and Acinetobacter baumannii Isolated from a Sepsis Patient with Pauci-Immune Crescentic Glomerulonephritis, India.

Acinetobacter baumannii and Enterococcus faecalis are opportunistic bacteria frequently associated with hospital-acquired infections. A. baumannii nosocomial infections in intensive care units are a worldwide problem, with high mortality rates. It may also develop rapidly multidrug resistance (MDR), extensive drug resistance (XDR), and even pan-drug resistance (PDR). Colistin resistance which is an example of pan-drug resistance, is highly alarming as it's used as a last-line antibiotic. Microbes capable of crossing epithelial barriers such as E. faecalis have developed novel strategies to counter antimicrobial agents and cause bacteremia in immunocompromised patients. However, the coinfection of these bacteria in the same patient is unusual. Here, we report a genomic investigation of the extensively drug-resistant E. faecalis and A. baumannii isolated from the blood sample of a patient diagnosed with pauci-immune crescentic glomerulonephritis (PICGN). Identification of cultures isolated from blood sample was carried out using whole-genome sequencing and resistome profiles were mapped. Whole genome sequencing revealed that E. faecalis SVJ-EF01 had a genome size of2,935,226bp and GC content of 37.4%, whereas A. baumannii SVJ-AC01 had a genome size of 3,730,857bp and GC content of 39%. Draft genomes were functionally annotated demonstrating that the organism harbors multiple virulence factors and antimicrobial-resistant mechanisms including MDR efflux pumps. A. baumannii genome possessed a CRISPR-Cas system which might contribute to antimicrobial resistance. This highlights the significance of polymicrobial nature in ESKAPE pathogenesis research. This genomic investigation helps to gain insights into the virulence, resistance profile, and functional potential of these pathogens.

Interrelation Between Pathoadaptability Factors and Crispr-Element Patterns in the Genomes of Escherichia coli Isolates Collected from Healthy Puerperant Women in Ural Region, Russia.

Escherichia coli is a commensal and opportunistic bacterium widely distributed around the world in different niches including intestinal of humans and animals, and its extraordinary genome plasticity led to the emergence of pathogenic strains causing a wide range of diseases. E. coli is one of the monitored species in maternity hospitals, being the main etiological agent of urogenital infections, endometriosis, puerperal sepsis, and neonatal diseases. This study presents a comprehensive analysis of E. coli isolates obtained from the maternal birth canal of healthy puerperant women 3-4 days after labor. According to whole genome sequencing data, 31 sequence types and six phylogenetic groups characterized the collection containing 53 isolates. The majority of the isolates belonged to the B2 phylogroup. The data also includes phenotypic and genotypic antibiotic resistance profiles, virulence factors, and plasmid replicons. Phenotypic and genotypic antibiotic resistance testing did not demonstrate extensive drug resistance traits except for two multidrug-resistant E. coli isolates. The pathogenic factors revealed in silico were assessed with respect to CRISPR-element patterns. Multiparametric and correlation analyses were conducted to study the interrelation of different pathoadaptability factors, including antimicrobial resistance and virulence genomic determinants carried by the isolates under investigation. The data presented will serve as a valuable addition to further scientific investigations in the field of bacterial pathoadaptability, especially in studying the role of CRISPR/Cas systems in the E. coli genome plasticity and evolution.

Emergence of Carbapenem-Resistant Uropathogenic Escherichia coli (ST405 and ST167) Strains Carrying blaCTX-M-15, blaNDM-5 and Diverse Virulence Factors in Hospitalized Patients.

Urinary tract infections (UTIs) are common infectious diseases in hospital settings, and they are frequently caused by uropathogenic Escherichia coli (UPEC). The emergence of carbapenem-resistant (Carb-R) E. coli strains poses a significant threat due to their multidrug resistance and virulence. This study aims to characterize the antimicrobial resistance and virulence profiles of Carb-R UPEC strains isolated from hospitalized patients. A total of 1100 urine samples were collected from patients in Lahore and Faisalabad, Pakistan, between May 2023 and April 2024. The samples were processed to isolate and identify E. coli using standard microbiological techniques and VITEK®2, followed by amplification of the uidA gene. Antimicrobial susceptibility was evaluated using the Kirby-Bauer disc diffusion method and broth microdilution. Resistance and virulence genes were detected through PCR and DNA sequencing, and sequence typing was performed using MLST. Among the 118 Carb-R UPEC isolates, resistance was most frequently observed against sulfamethoxazole-trimethoprim (96.6%) and doxycycline (96.6%). All of the isolates remained sensitive to colistin and tigecycline. Sequence types ST405 (35.6%) and ST167 (21.2%) were predominant and carried the blaCTX-M-15 and blaNDM-5 genes. The distribution of virulence genes and a variety of antimicrobial resistance genes (ARGs), conferring resistance to aminoglycosides, fluoroquinolones, tetracyclines, and sulfonamides, were observed as specifically linked to certain sequence types. This study provides insights into the molecular epidemiology of carbapenem-resistant Uropathogenic E. coli (Carb-R UPEC) strains and highlights the presence of globally high-risk E. coli clones exhibiting extensive drug resistance phenotypes in Pakistani hospitals. The findings underscore the urgent need for enhanced surveillance and stringent antibiotic stewardship to manage the spread of these highly resistant and virulent strains within hospital settings.

Comparison of genotypic features between two groups of antibiotic resistant Klebsiella pneumoniae clinical isolates obtained before and after the COVID-19 pandemic from Egypt

Klebsiella pneumoniae is a common pathogen capable of causing a wide range of infections. Antibiotic resistance complicates treatment of these infections significantly. We are comparing resistance levels and genotypes among two collections of K. pneumoniae clinical isolates from Alexandria Main University Hospital (AMUH). We used disc diffusion and Minimum Inhibitory Concentration (MIC) by microbroth dilution to assess resistance levels and performed whole genome sequencing (WGS) to describe multilocus sequence types (MLST) and resistance gene presence. Among a collection of 56 K. pneumoniae clinical isolates (19 from 2019 to 37 from 2021), multidrug resistance (MDR) was 33% and 10%, extended drug resistance (XDR) was 24% and 46% and pan-drug resistance (PDR) was 43% and 43%, respectively. We identified 15 MLST STs including two novel types (ST-6118 and ST-6119 ). ST-101 and ST-383 were common between the two collections; ST-101 was the most common genotype in 2019 (28.6%) and ST-147 was most common in 2021 (25%). Ampicillin/sulbactam, amikacin, cefepime, ceftriaxone and ertapenem MICs were significantly higher in 2021. Prevalence of aph(3’) – Ia, aph(3’)-VI, mphA was significantly higher in 2021. The increasing resistance levels and the persistence of some MDR/XDR genotypes is concerning. Understanding mechanisms of resistance will inform infection control and antimicrobial stewardship plans to prevent evolution and spread of XDR and PDR strains.

Serotype distribution and antimicrobial resistance of Streptococcus pneumoniae isolated from children in Japan, 2023

BackgroundThe prevalence of serotypes and antimicrobial resistance of Streptococcus pneumoniae was characterized among children thirteen years after the licensure of the pneumococcal conjugate vaccine (PCV) in Japan. MethodsA total of 353 pneumococcal isolates were collected from Japanese children between March and July 2023. All the isolates were serotyped using genetic methods and tested for susceptibility to 14 antimicrobial agents. ResultsAmong the 353 isolates, the prevalence rates of non-PCV13 and non-PCV20 serotypes were 96.9 % and 77.9 %, respectively, including the dominant non-PCV13/PCV20 serotypes 23A (16.1 %), 35B (15.3 %), 15A (10.5 %), 15C (9.3 %), and 34 (9.1 %), which accounted for 60.3 % of all isolates. The high non-susceptibility rates were observed for macrolides (erythromycin, azithromycin, and clarithromycin; ≥81.9 %) and tetracycline (80.7 %). Penicillin non-susceptibility and multidrug resistance (MDR) were detected in 49.9 % (6.8 % resistant and 43.1 % intermediate) and 68.3 % of the isolates, respectively. The three most common non-PCV13/PCV20 serotypes 15A, 23A, and 35B exhibited high prevalence rates of penicillin non-susceptibility (≥89.5 %) and MDR (≥81.5 %). Extensive drug resistance was observed in 10.5 % of all isolates belonging to six different serotypes (12F, 23A, 11A, 15A, 35B, and 15B) and in the non-encapsulated strains of S. pneumoniae. ConclusionsOur study revealed a higher prevalence of non-susceptibility to penicillin with MDR in the three most common non-PCV13/PCV20 serotypes 15A, 23A, and 35B, in Japan, suggesting their persistence in the PCV13 era.

Resistance patterns, virulence determinants, and biofilm genes of multidrug-resistant Pseudomonas aeruginosa isolated from fish and fish handlers

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium that is widely distributed in aquatic environments and causes major economic losses in fish and public health hazards.This study aimed to identify the occurrence of P. aeruginosa in samples collected from fish and fish handlers, and to investigate the antimicrobial susceptibility, virulence determinants, and biofilm genes of P. aeruginosa isolates. A total of 276 samples were cross-sectionally collected from Nile tilapia (53), Golden grey mullet (52), Mediterranean horse mackerel (50), Striped red mullet (71), and fish handlers (50) at five different retail fish markets in Damietta Governorate, Egypt. Pseudomonas species (spp.) were biochemically identified in 57.9% of the total examined samples. Peudomonas aeruginosa were the most prevalent species isolated from the fish and human samples via PCR technique. Peudomonas aeruginosa isolates exhibited full resistance (100%) to tobramycin (TOB), gentamicin (CN), and colistin (CL), with a high level of susceptibility (88.5%) to imipenem (IPM) using the disk diffusion method. Most P. aeruginosa isolates (84.6%) exhibited drug resistance, with 61.5% were multidrug resistance (MDR) and 23.1% were extensive drug resistance (XDR). Most isolates had at least four virulence-associated genes (lasB, toxA, exoU, and oprL) and three biofilm genes (psIA, peIA, and lasR) by using uniplex PCR. The lasI, and rhlR Quorum Sensing (QS) genes were identified in 84.6% and 61.5% in the examined P. aeruginosa isolates, respectively. The highest mortality rate in Nile tilapia experimentally infected with P. aeruginosa isolate encoding most of virulent genes. Multivariate analyses revealed high heterogeneity among the examined isolates. This study revealed the emergence of virulent and drug resistant P. aeruginosa isolates in fish, poses high risks to consumers and food. Thus, strict hygienic measures should be considered when catching, handling, and storing fish, in addition to the routine application of antimicrobial susceptibility testing.

Effectiveness of new antituberculosis drugs in the treatment of children and adolescents with chemoresistant tuberculosis

BACKGROUND. There is a significant decrease the effectiveness of antituberculous (anti-TB) treatment on the background of multidrug and extensive drug resistance (MDR/XDR) of Mycobacterium tuberculosis. Therefore, in order to increase the effectiveness of treatment MDR-/XDR-TB a new antimycobacterial drugs such as bedaquiline (Bdq), delamanid (Dlm) and pretomanid have been introduced both for adults, children and adolescents in recent years. MATERIALS AND METHODS. On the basis of a retrospective cohort analysis of the data of patients' medical records the evaluation of the clinical effectiveness of chemotherapy with Bdq and Dlm was carried out. The main group: 40 children and adolescents with MDR-/XDR-TB of lungs, who received complex antimycobacterial therapy (AMBT) with Bdq and Dlm. The control group consisted of 27 patients who received complex AMBT without Bdq and Dlm. Age range – from 3 to 18 years. RESULTS AND DISCUSSION. On the background of AMBT during the first 3 months of treatment was established stopping bacterial secretion among all patients of main and control groups. However, in control group compare to main one stopping bacterial secretion was significant slowly (p<0.05). At the stage of completion of the intensive phase of AMBT, the normalization of immunological indicators occurred in 29.6±2.8 % of control group and in 43.4±4.5 % of main one. A significant difference between the groups among the immunoregulatory index CD3+CD4+/CD3+CD8+, IgM and circulating immune complexes was obtained. Among children and adolescents of the main group positive dynamic of immunological changes were observed 1.5 times more often. Among all patients of main group the resolution of the infiltration, consolidation of the focus and the absence of decay cavities were ascertained at the end of the anti-TB course. Anti-TB treatment with the formation of small residual changes into lung tissue ended in 77.5 % patients of main group. In 12.5 % cases of control group destructions persisted and bacterial excretion resumed. A large residual changes such as multiple dense foci, fibrosis and residual decay cavities in control group were observed 2.3 times more often (51.9 % vs 22.5 %), p<0.05, than in main one. Using Bdq and Dlm among children and adolescents with MDR-/XDR-TB significantly increased efficiency of complex treatment. Among main group (72.5 %) compare to control (33.3 %) one the results of treatment to be considered “cured” were 2.2 times more likely and 1.5 times less often – “completed” (27.5 % vs 51.8 % respectively). The success rate of treatment among children and adolescents who received Bdq and Dlm was 100.0 % and among patients without these new drugs – 85.2 %. CONCLUSIONS. The criteria used show that AMBT combined with Bdq and Dlm is 1.5-2.2 times more effective (according to a separate criterion) than AMBT without these drugs.

Antibiotic susceptibility of uropathogens: a 3-year retrospective study at Ho Teaching Hospital of Ghana

BackgroundUrinary tract infection (UTI) remains one of the most treated infections in primary healthcare over the last two decades. The infection is treated with antibiotics. However, there have been reported cases of increasing antibiotic resistance globally, limiting the available antibiotics for the treatment of the infection. The study aimed to determine the frequency of bacterial urinary tract infections and their antibiotic resistance pattern in Ho Teaching Hospital of Ghana from 2019–2021.MethodologyData on urine culture and susceptibility testing and patient demographics from 2019–2021 were collected from the microbiology unit archives with a designed Microsoft Excel 2019 form and later exported to IBM SPSS (v26) for statistical analysis on the uropathogens and their antibiotic resistance pattern. P-value < 0.05 was considered statistically significant.ResultsOut of 4806 records, 1005 bacterial isolates were found, with a total prevalence of 20.91%. The most prevalent group of organisms was the Enterobacteriaceae, with E. coli 409 (40.70%) being the most frequent isolate. Of the 772 isolates subjected to amikacin, 48(6.22%) and 6(0.78%) of the Gram-negative and Gram-positive bacterial organisms showed resistance to the antibiotic respectively. 58.96% (148/251) and 3.59% (9/251) of Gram-negatives and Gram-positives were resistant to cotrimoxazole. Out of the 1005 bacterial isolates, 165(16.42%), 161(16.02%) and 2(0.20%) showed multidrug resistance (MDR), extensively-drug resistance (XDR), and pandrug resistance (PDR) respectively.ConclusionThere was a high antibiotic-resistant pattern among the uropathogens reported in this current study, hence, the Standard Treatment Guidelines may need to be updated to reflect the high rates of antibiotic resistance exhibited by most prevalent isolates.

Periodic phenotypic profile analysis of Acinetobacter baumannii drug resistance characteristics showing the emergence of PDR.

Acinetobacter baumannii, one of the ESKAPE pathogens, is on the World Health Organization (WHO) list of priorities needing urgent new effective antimicrobial agents due to exhibited high resistance by the bacterium to currently available antibiotics. This study examines the periodic changes of clinical A. baumannii isolates and their antimicrobial resistance patterns and types in Southeastern region of Saudi Arabia. One hundred and seventy-seven randomly selected A. baumannii isolates were used for the investigation with bacterial identities (IDs) and antimicrobial assay ascertained with Gram-negative (GN) ID cards and antimicrobial susceptibility test (AST) cards of Vitek 2 Compact Automated System according to manufacturer's guidelines. Descriptive phenotypic types of isolates were compared using comparison proportion and Fisher extraction test, while Morpheus versatile matrix visualization and analysis software was used for the dendrogram of hierarchical clustering. A significantly higher proportion of samples were from males compared to females (p = 0.025), with 33.33% of samples originating from patients aged 51-70 years. Resistance was high for imipenem (93%), meropenem (94%), levofloxacin, ciprofloxacin (99%), and aztreonam (98%). There was less percentage resistance to colistin (18%), tigecycline (23%), and minocycline (23%). Multidrug resistance (MDR)/carbapenem-resistant Acinetobacter baumannii (CRAB) was observed consistently across all years. There was no extensive drug resistance (XDR) among isolates from 2013 to 2014, but it was present in the 2016 to 2018 and 2019 to 2020 periods, while pandrug resistance was seen only in the 2019 to 2020 isolates. The study shows a clear trend of the isolates changing from MDR to XDR and then to pandrug resistance over the study period. Also, it indicates that carbapenems might no longer be a treatment choice in this study region. Although colistin exhibited less resistance, the toxicity of the drug reduces its usefulness. The development of pandrug resistance is a critical concern.

Clinical Characteristics and Molecular Insights of Carbapenem-Resistant Klebsiella pneumoniae Isolates from Patients in Intensive Care Units.

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP), a significant worldwide public health threat, is common in patients in intensive care units. Methods: A retrospective study was conducted over a period of 22 months to assess the risk factors associated with infection caused by CRKP isolates. Strain identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antimicrobial sensitivity was assessed using the micro broth dilution method and Kirby-Bauer test. The genes blaKPC, blaOXA-48, blaNDM, blaVIM, and blaGES were amplified using polymerase chain reaction (PCR), followed by sequencing of the PCR products. The polymerase hypermucoviscosity phenotype was determined using the string test. Capsular serotypes (K1, K2) and presence of the virulence gene (rmpA) in positive isolates were investigated using phenotypic tests followed by PCR. Results: Length of hospitalization and use of carbapenems were associated with CRKP infection. CRKP isolates exhibited extensive drug resistance, but retained sensitivity to colistin and ceftazidime-avibactam (CZA). The main gene detected in 35 CRKP isolates was blaKPC-2. In addition, 11 strains were positive in the string test, and two of these strains carried rmpA. Conclusions: Prolonged hospitalization and carbapenem exposure increased the risk of CRKP infection in intensive care unit (ICU) patients. The prevalence of CRKP carrying the blaKPC-2 gene was high, and suspected hypervirulent carbapenem-resistant K. pneumoniae isolates were scattered.

Prediction of structure of mycobacterial efflux pump protein Rv0194 and molecular dynamics simulation of the predicted structures

Tuberculosis is a major cause of morbidity and mortality primarily in developing nations. The rising number of cases of multidrug resistance and extensive drug resistance are a critical concern for the management of the condition. Even though new antibiotics are being developed, eventually there are also strains that are resistant to them. The evolution of resistance in Mycobacterium tuberculosis is significantly influenced by drug efflux caused by efflux pumps. Rv0194 is an important efflux pump associated with resistance to multiple drugs like beta lactam antibiotics like ampicillin and also erythromycin and novobiocin. The introduction of efflux inhibitors for Rv0194 could shorten the course of current therapy and improve the efficacy of second-line medications. Building a trustworthy molecular model of this efflux pump is the goal of this study. We created 3 models using different modeling tools. These models were then subjected to a 20 ns molecular dynamics simulation in a lipid bilayer. We find that the model built by Swiss Model shows the best results in molecular modeling and validation and the structure is also stable throughout the 20 ns MD simulations. Consequently, this model is reliable and can be used for further studies.

Screening of the Pandemic Response Box library identified promising compound candidate drug combinations against extensively drug-resistant Acinetobacter baumannii

Infections caused by antimicrobial-resistant Acinetobacter baumannii pose a significant threat to human health, particularly in the context of hospital-acquired infections. As existing antibiotics lose efficacy against Acinetobacter isolates, there is an urgent need for the development of novel antimicrobial agents. In this study, we assessed 400 structurally diverse compounds from the Medicines for Malaria Pandemic Response Box for their activity against two clinical isolates of A. baumannii: A. baumannii 5075, known for its extensive drug resistance, and A. baumannii QS17-1084, obtained from an infected wound in a Thai patient. Among the compounds tested, seven from the Pathogen box exhibited inhibitory effects on the in vitro growth of A. baumannii isolates, with IC50s ≤ 48 µM for A. baumannii QS17-1084 and IC50s ≤ 17 µM for A. baumannii 5075. Notably, two of these compounds, MUT056399 and MMV1580854, shared chemical scaffolds resembling triclosan. Further investigations involving drug combinations identified five synergistic drug combinations, suggesting potential avenues for therapeutic development. The combination of MUT056399 and brilacidin against A. baumannii QS17-1084 and that of MUT056399 and eravacycline against A. baumannii 5075 showed bactericidal activity. These combinations significantly inhibited biofilm formation produced by both A. baumannii strains. Our findings highlight the drug combinations as promising candidates for further evaluation in murine wound infection models against multidrug-resistant A. baumannii. These compounds hold potential for addressing the critical need for effective antibiotics in the face of rising antimicrobial resistance.

GENETIC VARIABILITY AND GEOGRAPHIC DISTRIBUTION OF MYCOBACTERIUM TUBERCULOSIS LINEAGE 2

Mycobacterium tuberculosis (MTB) is a substantial threat to public health, infecting approximately 10 million individuals annually with tuberculosis. Among the genetic lineages of MTB, lineage 2 (L2), notably the Beijing family, plays a significant role in global tuberculosis epidemiology, accounting for nearly a quarter of all reported TB cases. Originating possibly in East Asia, this lineage spread globally, causing significant epidemics in Central Asia, Eastern Europe, and Eastern Africa. Geographic variability in the distribution of MTB L2 strains reveals diverse prevalence patterns among sublineages across different regions. L2.1 (proto-Beijing) is primarily composed of isolates originating from China, Thailand, and Vietnam, with a smaller number from Japan, Malaysia, and Indonesia. The ancestral sublineage, named L2.2.A, is mostly spread in China, Japan, and Thailand, while the modern sublineage, L2.2.M, is widespread, spanning almost the entire world. Moreover, the L2.2.M1 clade demonstrates a wide geographic spread, encompassing various countries across Asia and Australia, while other subclades of the L2.2.M2, L2.2.M3, and L2.2.M4 clades show more localized distributions across different regions. The L2.2.M4 clade comprises nine subclades, L2.2.M4.1 and L2.2.M4.2 are primarily found in Thailand, while L2.2.M4.3, L2.2.M4.6, and L2.2.M4.8 predominate in China. In South Africa, L2.2.M4.4 is the predominant subclade, whereas L2.2.M4.7 is associated with Nepalese isolates. In contrast, in regions such as Central Asia, Eastern Europe, and Russia, L2 strains, particularly the Modern Beijing sublineage, dominate. Notable examples include Europe/Russia W148 outbreak L2.2.M4.5 (B0W/148), Central Asia L2.2.M4.9 (CA), Central Asia outbreak L2.2.M4.9.1 (CAO), and Clade A L2.2.M4.9.2. Additionally, recent small clades like L2.2.M5 and L2.2.M6, originating from Vietnam, Thailand, and China, have emerged, with L2.2.M6 also detected in Kenya and South Africa. In Kazakhstan, we have identified such sublineages of L2 as CAO (n=69; 67.64%) L2.2.M4.9.1, CA (n=27; 26.47%) L2.2.M4.9, B0W/148 (n=5, 4.90%) L2.2.M4.5 and one isolate representative of a rare L2.2.M4 lineage (n =1; 0.98%). Strains of this lineage demonstrate the development of multidrug resistance (MDR) and extensive drug resistance (XDR), reflecting the emergence of resistance mechanisms against all available anti-tuberculosis drugs. In summary, M. tuberculosis lineage 2, especially the Beijing family, significantly impacts global tuberculosis epidemiology, with diverse prevalence patterns among sublineages across regions.

Evaluation of Antibiotic Susceptibility, Carbapenemase and Metallobetalactamase-producing Strains of Acinetobacter baumannii Isolated from Hospitalized Patients in Zahedan During 2019 - 2022

Background: Microbial resistance caused by Acinetobacter baumannii, which leads to various infectious diseases, is projected to result in ten million deaths by 2050. This is mainly due to the production of beta-lactamase enzymes, a significant concern for the World Health Organization. Objectives: This study utilized phenotypic analysis to examine isolates producing metallo-beta-lactamase and carbapenemase and to determine the pattern of antibiotic resistance in Acinetobacter baumannii. Methods: Following the isolation and identification of 372 Acinetobacter baumannii strains from clinical isolates using a variety of biochemical tests, the antibiotic resistance pattern was examined using the disc diffusion method. The production of beta-lactamase and carbapenemase was determined using the combined disc diffusion phenotypic test (CDDT) and the Modified Hodge Test (MHT), respectively. Results: Based on this study, minocycline (7.4%) exhibited the lowest resistance rate, while carbapenems (imipenem and meropenem) showed the highest resistance. All antibiotic groups demonstrated over 80% resistance, suggesting extensive drug resistance in all samples. Furthermore, 325 (94.6%) strains of Acinetobacter baumannii produced metallo-beta-lactamase, 215 (57.7%) strains strongly produced carbapenemase, and 135 (36.1%) strains weakly produced carbapenemase. Conclusions: Due to minimal resistance to colistin, minocycline, and ampicillin-sulbactam, it is advisable to use these drugs either individually or in combination for treatment.

Co-Prevalence of Quinolone Resistance and Extended-Spectrum Beta-Lactamases among Clinical Enterobacteriaceae Isolates from a Tertiary Hospital in Katsina, Nigeria

Study’s Novelty/Excerpt This study investigates the co-existence of Extended-Spectrum Beta-Lactamases (ESBLs) and quinolone resistance among clinical Enterobacteriaceae isolates, highlighting the high prevalence of multidrug resistance (MDR) and extensive drug resistance (XDR). By employing the VITEK-2 Compact automated identification system, the research demonstrates that a significant proportion of quinolone-resistant Enterobacteriaceae are also ESBL-positive, with co-resistance observed primarily in Escherichia coli and Klebsiella pneumoniae. These findings emphasize the critical need for continuous surveillance and antibiotic stewardship to mitigate the growing threat of antimicrobial resistance and align with Sustainable Development Goals (SDG) 3 for good health and well-being. Full Abstract Antimicrobial resistance (AMR) poses a major hazard to global public health. It reduces the effectiveness of many antibiotics, making infections harder to cure and raising the likelihood of disease transmission and death. Globally, beta-lactam and quinolone antibiotics are among the commonly prescribed medications. Yet, a multitude of bacteria have evolved distinct multidrug resistance (MDR) characteristics, rendering many of these important drugs worthless. This study aimed to investigate the magnitude of the simultaneous occurrence of Extended-Spectrum Beta-Lactamases (ESBLs) and Quinolone-resistance (co-existence) among clinical Enterobacteriaceae isolates. A total of 95 Enterobacteriaceae pathogens isolated from different human samples were obtained from a Tertiary Hospital in Katsina. Then, the VITEK-2 Compact automated identification system was employed for the identification and antimicrobial susceptibility testing (AST) and the ESBL screening of isolates. This study showed that out of the total 95 isolates, 67 (70.5%) were quinolone-resistant, while 53 (55.8%) were ESBL-positive. Most of the quinolone-resistant (QRE) Enterobacteriaceae were ESBL-positive, 50 (74.6%), and conversely, most of the ESBL-positive Enterobacteriaceae were quinolone-resistant (50, 94.3%). Co-resistance (quinolone-resistance and ESBL-positive) was recorded in 50 (52.63%) of the isolates, all belonging to the Escherichia coli (42, 84.0%) and Klebsiella pneumoniae (8, 16.0%). Almost all the co-resistant isolates were resistant to the tested quinolones [Ciprofloxacin (49, 98.0%) and Levofloxacin (50, 100.0%). The lowest resistance was recorded to Ertapenem(6.0%), Meropenem (6.0%), and Amikacin (2.0%), and the highest to Ampicillin, Piperacillin and Levofloxacin (100.0% each). Almost all the co-resistant isolates were multidrug-resistant (MDR), 49 (98.0%), while 33 (66.0%) were extensively drug-resistant (XDR). According to the collected samples’ demographic data, the highest prevalences were recorded among males (60.0%, based on gender), adults (50.0%, based on age), and urine (48.0%, based on sample). Continuous surveillance and stewardship are essential to achieve good health and well-being (Sustainable Development Goal 3).

A Retrospective Case Series Study of Alcaligenes faecalis Pneumonia

Background: The potentially developing human pathogen Alcaligenes faecalis is a Gram-negative, nonfermenting bacterium. Treatment of A. faecalis infections is frequently difficult due to increased resistance to many antibiotics, such as β-lactam antibiotics, aminoglycosides, and quinolones. In the literature, A. faecalis pneumonia has never been documented in a case series study. Here, we provide a case series study of patients with A. faecalis pneumonia. Objectives: The aim of this study was to elucidate the clinical characteristics, management strategies, and outcomes of A. faecalis pneumonia patients. Methods: Patients with A. faecalis pneumonia between January 2014 and December 2019 were included in a retrospective investigation. We examined the clinical outcomes of patients with A. faecalis pneumonia, together with the risk factors for pneumonia, prior intravenous antibiotic use within 90 days, respiratory secretion culture results, antibiotic sensitivity test results, and other variables. Results: Observations revealed eight patients with A. faecalis pneumonia, including six males and two females. The mean age of patients was 70 years. These eight patients shared risk factors for pneumonia. Six patients were discharged, and two patients died as a result of A. faecalis pneumonia. Two patients with pneumonia caused by extensively drug-resistant A. faecalis were identified. Conclusions: Rare cases of A. faecalis pneumonia have been documented in the literature. Recently, A. faecalis has developed extensive drug resistance. To treat pneumonia caused by A. faecalis with substantial antibiotic resistance, either polymyxin B or tigecycline is needed. The clinical outcome is typically satisfactory when A. faecalis pneumonia patients receive appropriate antibiotic therapy, but cases of fatal pneumonia have been documented in the literature.

New Delhi metallo-β-lactamases among extensively drug-resistant clinical isolates from Lahore, Pakistan.

Aim: The study determines rates of carbapenem resistance (CR) and frequency of blaNDM in multidrug-resistance (MDR) or extensivedrug resistance (XDR), and evaluates the potential of phenotypic tests for detecting NDMproduction. Materials & methods: Singleplex PCR was used to detect blaNDM. Phenotypic tests, including combination disc test (CDST) and modified Hodge test (MHT), were evaluated for NDM production. Results: Among 338 CR isolates, 47.63% were MDR, whereas 52.36% were XDR with 53.25% carrying blaNDM. MHT was found to bediscriminativefor detecting NDM production, whereas no significant association was observed for CDST. Conclusion: The high incidence of CR and MDR and XDR isolates possessing blaNDM presents an impending threat in therapeutics. Limitations of phenotypic tests suggest better testing, including molecular detection of the enzyme.

Comparison of Colistin Susceptibility via Two Different Methods in Gram-Negative Extensive Drug-Resistance Isolates from ICU Patients.

To compare the susceptibility of colistin by two methods in extensive drug-resistant (XDR) Gram-negative isolates from ICU patients. Cross-sectional comparative analysis. Place and Duration of the Study: Department of Microbiology, Combined Military Hospital Karachi, Pakistan, from August 2022 to February2023. A total of 100 clinical specimens received from the intensive care unit yielded growth of extensively drug-resistant gram-negative bacteria, which were evaluated for polymyxin E susceptibility. The agar dilution method was compared with the reference broth microdilution (BMD) method. Minimum inhibitory concentration (MIC) was noted for both methods. Comparison of the MIC method by agar dilution showed a 90% correlation with the reference method of broth microdilution. With MICs within the acceptable range of the clinical and laboratory standards institute (CLSI) recommendations, 89 isolates were susceptible to colistin, whereas only 11 remained resistant. Polymyxin E's MIC 50 and MIC 90 were determined to be 1 and 2 µg/ml, respectively, with 97% susceptibility. Agar dilution susceptibility method can be used for screening purposes for the susceptibility testing of polymyxin E. This method is reliable and can easily identify the heteroresistance. Extensively drug-resistant, Broth microdilution, Multidrug-resistant, Agar dilution, Minimum inhibitory concentration, Colony forming unit.