blaOXA Genes Research Articles

Co-occurrence of blaNDM-1 and blaOXA-23 in carbapenemase-producing Acinetobacter baumannii belonging to high-risk lineages isolated from burn patients in Tunisia.

Carbapenem-resistant Acinetobacter baumannii (CR-Ab) is an important cause of infections in burn patients. This study aimed to characterize the antimicrobial susceptibility pattern of CR-Ab isolated from burns in Burn Intensive Care Unit (BICU) of the Trauma and Burn Centre of Ben Arous, to determine the prevalence of β-lactamase-encoding genes and to search eventual genetic relatedness of CR-Ab strains. From 15 December 2016 to 2 April 2017, all nonduplicated CR-Ab isolated in burn patients in the BICU were screened by simplex Polymerase Chain Reaction (PCR) for the class A, B, C, and D β-lactamase genes. Sequencing was performed for NDM gene only. Genetic relatedness was determined by using pulsed field gel electrophoresis (PFGE) and by multilocus sequence typing. During the study period, 34 strains of CR-Ab were isolated in burns, mainly in blood culture (n=14) and central vascular catheter (n=10). CR-Ab strains were susceptible to colistin but resistant to amikacin (91%), ciprofloxacin (100%), rifampicin (97%), and trimethoprim-sulfamethoxazole (100%). All strains harbored blaOXA-51-like and blaOXA-23 genes, only or associated to blaGES (n=26; 76%), blaADC (n=20; 59%), blaPER-1 (n=6; 18%) or/and blaNDM-1 (n=3; 9%). PFGE identified 16 different clusters and revealed that most strains belonged to one major cluster A (n=15; 44.1%). Among NDM-1 isolates, two were clonally related in PFGE and belonged to two single locus variant sequence type ST-6 and ST-85. This is the first description of clonally related NDM-1 and OXA-23-producing A. baumannii strains in the largest Tunisian BICU associated with two single locus variant sequence types ST6 and ST85.

Phenotypic and Molecular Detection of Carbapenemase-Producing Klebsiella pneumoniae Isolated from Patients Admitted to Teaching Hospitals in Shiraz, Iran

Background: Carbapenem-resistant Klebsiella pneumoniae (Cr-KPN) poses a significant global public health challenge. Objectives: This study aimed to investigate the prevalence and expression levels of carbapenemase-encoding genes in Cr-KPN isolated from patients admitted to teaching hospitals in Shiraz, Iran. Methods: A total of 671 distinct clinical samples were collected from two teaching hospitals in Shiraz. Initial identification and final confirmation of K. pneumoniae isolates were carried out using conventional biochemical tests and PCR assays, respectively. The detection of carbapenemase-producing K. pneumoniae, both phenotypically and genotypically, was performed through modified carbapenem inactivation methods (mCIM) and multiplex PCR assays. Real-time PCR was utilized to assess the expression levels of carbapenemase-encoding genes. Results: The overall frequency of K. pneumoniae strains was 14.9% (n = 100/671). mCIM indicated that 26% of K. pneumoniae isolates exhibited carbapenemase production. Furthermore, 24% and 17% of K. pneumoniae isolates demonstrated resistance to imipenem and meropenem, respectively. The blaIMI/IMP gene was detected in 91% of the isolates. Among imipenem-resistant isolates, 62.5% tested positive for the blaOXA-48 gene. Additionally, 29.4%, 76.5%, and 11.8% of meropenem-resistant isolates were positive for the blaKPC, blaOXA-48, and blaNDM genes, respectively. Real-time PCR analysis revealed increased expression levels of blaKPC (1.66-fold), blaOXA-48 (7.30-fold), blaNDM (4.22-fold), and blaIMI/NMC (2.39-fold) genes in resistant isolates when exposed to imipenem. Conclusions: These findings underscore the significance of establishing active surveillance networks to monitor and track the dissemination of carbapenemase-producing K. pneumoniae, which presents a global public health threat.

Evaluation of Phenotypic Tests for Carbapenemase Detection in Enterobacteriaceae in Tunisia.

Introduction: Resistance to carbapenems in Enterobacteriaceae is a challenge for public health. Carbapenemase production is the leading mechanism. This work aims to evaluate four phenotypic methods for carbapenemase detection in comparison with a molecular method. Materials and Methods: Thirty-seven nonrepeating Enterobacteriaceae strains with decreased susceptibility to ertapenem were included. Imipenem MIC, Modified Hodge Test (MHT), Neo-Rapid Carb Kit® and KPC, MBL, and OXA-48 Confirm Kit® were performed. Isolates were tested for blaOXA-48, blaNDM, and blaVIM genes by end-point polymerase chain reaction. The results of the molecular study were used as a reference test to determine the performances of the phenotypic tests. Results: Imipenem resistance does not seem to be a good marker for carbapenemase production with a sensitivity of 54% (95% CI: 38-71). MHT showed 82% sensitivity (95% CI: 65-91). Overall, the enzymatic test showed the best performances for carbapenemase detection with 100% sensitivity (95% CI: 89-100) and the best turnaround time. The characterization of carbapenemases classes by the combined discs test demonstrated 88% overall sensitivity (95% CI: 72-95). Conclusion: The results of this study support the combination of the enzymatic and the combined disc tests for carbapenemase detection in Enterobacteria.

Pediatric bacteremia and CNS infections associated with <i>klebsiella pneumoniae</i>: molecular genetic characteristics and clinical features

Klebsiella pneumoniae is one of the most significant and life-threatening pathogen of nosocomial infections. This opportunistic microorganism can cause infections of the bloodstream, respiratory tract, urinary tract, skin and soft tissues, inflammation of meninges of the brain and spinal cord, leading to elevated hospital mortality. The purpose of our study was a retrospective analysis of molecular genetic characteristics of K. pneumoniae isolated from blood and liquor samples as well as to describe clinical features in bacteremia and CNS infections. According to the results of assessed clinical data, K. pneumoniae isolates were selected from 64 children suffered from surgical pathology (congenital heart defects — 30%, abdominal pathology — 39%, severe combined trauma — 12%) and somatic diseases accompanied by antibacterial and/or glucocorticosteroid therapy — 14%. The minimum suppressive concentrations of antibiotics were determined by the broth micro-dilution method. Carbapenemases were detected by real time polymerase chain reaction. Virulence genes and capsule serotypes K1/K2 were assessed by multiplex PCR. Biofilms were grown using flat-bottomed polystyrene plates, followed by coloring, fixation, elution and data detection. The population diversity was assessed by multilocus sequence typing. Bacteremia and CNS infections associated with K. pneumoniae were fatal in 25% of cases. A substantial portion of the isolates demonstrated the phenotype of extremely drug resistance (XDR) — 43%, the phenotype of multidrug resistance (MDR) was shown in 16% of the isolates. The blaCTX-M cephalosporinase gene was found in 85% of the strains. The main determinant of resistance to carbapenems was the blaOXA-48 gene (33%); the blaNDM gene was detected in 9% of strains. The combination of blaOXA-48 and blaNDM was found in 7% of isolates. The study of biofilm production showed that moderate ability to form biofilms was shown in 61%, strong — 21%, and weak — 15% isolates. Two isolates (3%) did not form biofilms. The virulence genes entB and mrkD were detected in 100% of isolates, ybtS — in 78%. The iutA gene was found in 18% of the strains. Two isolates showed the presence of the kfu gene. Seven isolates belonged to the K2 serotype. 27 different genotypes were found in K. pneumoniae isolates examined. The most common were: ST307 — 21%, ST395 — 12%, ST48 — 7%, ST39 — 6% and ST29 — 6%. Infections of the bloodstream and central nervous system associated with K. pneumoniae have great importance in clinical practice. This microorganism is able to long persist on biotic and abiotic surfaces, has a wide natural and acquired resistance to antibiotics.

Genotypic characterization of bacterial isolates causing urinary tract infections among adults at Kiambu Level 5 Hospital, Kenya: selected extended-spectrum β-lactamase genes and biofilm formation.

The menace of antimicrobial resistance affecting public health is rising globally. Many pathogenic bacteria use mechanisms such as mutations and biofilm formation, significantly reducing the efficacy of antimicrobial agents. In this cross-sectional study, we aimed to determine the prevalence of selected extended-spectrum β-lactamase (ESβL) genes and analyse the biofilm formation abilities of the isolated bacteria causing urinary tract infection among adult patients seeking Medicare at Kiambu Level 5 Hospital, Kenya. The double-disc synergy test was used for phenotypic identification of ESβL-producing isolates, while microtitre plate assays with some modifications were used for the biofilm formation test. Ten isolates were bioassayed for ESβL genes out of 57 bacterial isolates obtained from urine samples. This study found the bla TEM genes to be the most prevalent ESβL type [10/10 (100 %)], followed by blaOXA and blaSHV genes at 4/10 (40 %) and 3/10 (30 %), respectively. In addition, co-carriage of blaTEM and blaSHV was 50 % lower than that of blaTEM+bla OXA genes at 66.7 % among Escherichia coli isolates studied. Biofilm formation was positive in 36/57 (63.2 %) of the isolates tested, with most being Gram-negative [25/36 (69.4 %)]. Escherichia coli [15/36 (41.7 %)], Klebsiella species [7/36 (19.4 %)] and Staphylococcus aureus [7/36 (19.4 %)] were the dominant biofilm formers. However, there was no significant difference in biofilm formation among all tested isolates, with all isolates recording P-values >0.05. In light of these findings, biofilm formation potential coupled with antimicrobial resistance genes in urinary tract infection isolates may lead to difficult-to-treat infections.

The European Union summary report on antimicrobial resistance in zoonotic and indicator bacteria from humans, animals and food in 2021-2022.

This report by the European Food Safety Authority and the European Centre for Disease prevention and Control, provides an overview of the main findings of the 2021-2022 harmonised Antimicrobial Resistance (AMR) monitoring in Salmonella spp., Campylobacter jejuni and C. coli from humans and food-producing animals (broilers, laying hens and fattening turkeys, fattening pigs and cattle under one year of age) and relevant meat thereof. For animals and meat thereof, AMR data on indicator commensal Escherichia coli, presumptive extended-spectrum beta-lactamases (ESBL)-/AmpC beta-lactamases (AmpC)-/carbapenemase (CP)-producing E. coli, and the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) are also analysed. Generally, resistance levels differed greatly between reporting countries and antimicrobials. Resistance to commonly used antimicrobials was frequently found in Salmonella and Campylobacter isolates from humans and animals. In humans, increasing trends in resistance to one of two critically antimicrobials (CIA) for treatment was observed in poultry-associated Salmonella serovars and Campylobacter, in at least half of the reporting countries. Combined resistance to CIA was however observed at low levels except in some Salmonella serovars and in C. coli from humans and animals in some countries. While CP-producing Salmonella isolates were not detected in animals in 2021-2022, nor in 2021 for human cases, in 2022 five human cases of CP-producing Salmonella were reported (four harbouring bla OXA-48 or bla OXA-48-like genes). The reporting of a number of CP-producing E. coli isolates (harbouring bla OXA-48, bla OXA-181, bla NDM-5 and bla VIM-1 genes) in fattening pigs, cattle under 1 year of age, poultry and meat thereof by a limited number of MSs (5) in 2021 and 2022, requires a thorough follow-up. The temporal trend analyses in both key outcome indicators (rate of complete susceptibility and prevalence of ESBL-/AmpC-producers in E. coli) showed an encouraging progress in reducing AMR in food-producing animals in several EU MSs over the last 7 years.

Exceptional prevalence of blaNDM-1 gene producing Enterobacter cloacae ssp. dissolvens isolated from hospitals in Baghdad

Background and aim: Hereine, we report for the first time the spread of balNDM-1 and other Extended spectrum B lactemase (ESβL) related genes among carbapenem-resistant Enterobacter cloacae ssp. dissolvens isolated from hospitals in Baghdad/Iraq. Methods: Thirty-one clinical and environmental Enterobacter spp. were isolated. Antimicrobial susceptibility testing was done by VITEK-2 system, Uniplex PCR amplification was carried out for detection of blaNDM-1 and bla OXA-48, Multiplex PCR for detection other Metalo B lactemase (MBL) genes For the detection of genes, which are blaIMP, blaVIM, blaSIM, blaGIM, and blaSPM. Results: Among thirty-one Enterobacter spp. isolates, 5 (16.12%) isolates classified as resistant to imipenem and meropenem together, according to MIC results, all isolates show high level of resistance 31 (100%) isolates to (amoxicillin/clavulanic acid and cefazolin, amikacin, ciprofloxacin), while resistance level ranged from 25 (80.6%) isolates to (ampicillin), 19 (61.3%) isolates resistant to trimethoprim/sulfamethoxazole, 17 (54.8%) resistant to gentamicin,15 (48.4%) resistant to ceftriaxone,11 (35.5%) isolates resistant to nitrofurantoin, 8 (25.8%)isolates resistant to cefepime piperacillin/tazobactam and tetracycline, whereas 6 (19.4%) islates resistant to aztreonam, 5 (16.1%) isolates resistant to meropenem, and finally 2 (6.5%) isolates resistant to levofloxacin. One isolate out of 5 which resistant to imipenem gave positive result in bla NDM−1 and Pre- NDM-1 gene, 2 isolates show positive result in bla VIM gene, all 5 isolates show positive resistant to IMI gene, While, none of these isolates gave any result in SIM, GIM, SPM and bla OXA-48 genes Conclusion: Carbapenem consider the last treatment to ESβL resistant isolates, but recently reported these isolates developed resistance towards antibiotics and produce carbapenemase and especially new-delhi-metallo-β-lactamase-1 (blaNDM-1) and cause increase the epidemiological situation resistance around the world.

PREVALENCE AND CHARACTERISATION OF EXTENDED-SPECTRUM BETA-LACTAMASES AND PLASMID-MEDIATED QUINOLONES RESISTANCE IN Enterobacteriaceae ISOLATED FROM COMPANION ANIMALS

Antimicrobial resistance is a major public health concern worldwide. This study aims to determine the prevalence of Enterobacterales producing beta-lactamase (TEM, SHV, OXA) or extended-spectrum beta-lactamases (ESBL), as well as plasmid-mediated resistance to quinolones (PMQR) (qnrA, qnrB, qnrS) in companion animals from the northeast region of Romania. A total of 124 faecal samples were collected aseptically from healthy dogs attending the veterinary practice for vaccination and cultivated on Brilliance ESBL medium (Oxoid, UK). The ESBL production testing was performed using the combination disc test. The identification of Enterobacterales strains was achieved using molecular identification and based on biochemical tests. Antimicrobial susceptibility testing was performed using the disk diffusion method. Identification of genes encoding for beta-lactamase enzymes and genes encoding plasmid-mediated resistance to quinolones was performed by PCR according to the protocols previously described. After ESBL screening, 31 (31/124; 25%) extended-spectrum cephalosporin (ESC)-resistant Enterobacterales were obtained, and 67.74% (21/31) of them were confirmed as ESBL-producers. Regarding the Enterobacterales species, 27 (27/31; 87.1%) were Escherichia coli and 4 (4/31; 12.9%) strains were Klebsiella pneumoniae. Among the ESBL-producing isolates, the blaCTX-M-1 gene group was predominant (58.82%), followed by the blaCTX-M-9 group (41.18%). The blaTEM, blaSHV and blaOXA gene groups were identified in 54.83%, 29.03% and 3.22% of the analysed strains, respectively. The prevalence of PMQR genes was 22.58% and consisted only of qnrS (19.35%) and qnrA (3.22%) genes. The prevalence of ESBL strains related to the total number of analysed samples was 16.93% (21/124). The findings show a significant prevalence of ESBLs and PMQR genes in Enterobacterales strains isolated from the faeces of healthy dogs, implying that pets may pose a risk of transmitting ESBL strains to other animals or owners.

Antimicrobial resistance profiles of Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae strains isolated from broiler chickens

Globally, the spread of multidrug-resistant Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae from food to humans poses a severe threat to public health. The aim of this study was to assess the co-occurrence of colistin and β-lactamase resistance genes in E. coli, K. pneumoniae, and P. aeruginosa strains isolated from faeces of abattoir broiler chickens. The E. coli, P. aeruginosa and K. pneumoniae isolates were successfully detected from faecal samples by polymerase chain reaction (PCR) at infection rates of 60.7%, 22.5% and 16.7% respectively. The isolates displayed the highest levels of antibiotic resistance (AR) against ampicillin (82.3%) and amoxicillin-clavulanic acid (74.2%) for E. coli, followed by cefoxitin (70.6%) for K. pneumoniae, whilst P. aeruginosa displayed 26.1% antibiotic resistance (AR) against both ampicillin and colistin sulphate. The colistin mcr-1 gene was harboured by 46.8%, 47.1% and 21.7%, E. coli, K. pneumonia and P. aeruginosa isolates respectively. Ten out of 62 (16.1%), 6/17 (35.3%), 4/23 (17.4%) isolates were phenotypically classified as ESBL E. coli, K. pneumoniae, and P. aeruginosa respectively. The ESBL-E. coli isolates respectively possessed blaCTX-M (60%), blaTEM (20%) and blaCTX-M-9 (10%) genes. The ESBL-K. pneumoniae harboured, blaCTX-M (50%), blaOXA (33%), blaCARB (17%), and blaCTX-M-9 (17%) genes respectively, whilst, P. aeruginosa isolates respectively carried blaTEM (75%), blaCTX-M (50%), blaOXA (25%) and blaCARB (25%) genes. Molecular analysis identified the blaCTX-Mβ-lactamase-encoding genes collectively from E. coli, P. aeruginosa, K. pneumoniae isolates. Colistin and β-lactamase genes were present in only 16.7%, 6.9%, and 2.9% of E. coli, K. pneumoniae, and P. aeruginosa isolates, respectively. A total of 17, 7 and 3 isolates for E. coli, K. pneumoniae and P. aeruginosa respectively carried both colistin and β-lactamase antibiotics resistant genes. This is a public health threat that points to a challenge in the treatment of infections caused by these zoonotic bacteria. Data generated from this study will contribute to formulation of new strategies for combating spread of E. coli, K. pneumoniae, and P. aeruginosa isolates as well as prevention of their AR development.

Different OXA-Carbapenemases in Genetically Unrelated Klebsiella pneumoniae Strains Isolated in a North Italian Hospital During Multidrug Resistance Screening.

Klebsiella pneumoniae is one of the main opportunistic pathogens that cause a broad spectrum of diseases with increasingly frequent acquisition of resistance to antibiotics, namely carbapenems. This study focused on the characterization of 23 OXA-48-like carbapenemase-producing K. pneumoniae isolates using phenotypic and molecular tests. Phenotypic determination of the presence of β-lactamases was performed using the extended-spectrum beta-lactamase (ESBL) NP test, and phenotypic determination of the presence of carbapenemase was based on the Carba NP test. Antimicrobial susceptibility tests were performed to assess the resistance against carbapenems. Molecular characterization of ESBL genes and carbapenemase genes (blaOXA-48, blaKPC, blaVIM, and blaNDM) was performed using polymerase chain reaction (PCR) techniques. In addition, K. pneumoniae strains were analyzed for their relatedness using multilocus sequence typing PCR analysis based on the Institut Pasteur protocol, which produces allelic profiles that contain their evolutionary and geographic pattern. Following further Sanger sequencing of the blaOXA-48 genes, no genetic mutations were found. Some OXA-48-producing K. pneumoniae isolates coharbored blaKPC, blaNDM, and blaVIM genes, which encode other carbapenemases that can hydrolyze carbapenem antibiotics. The final part of the study focused on the characterization of the plasmid profiles of all isolates to better understand the spreading of the IncL/M blaOXA-48 plasmid gene. The plasmid profile also revealed other incompatibility groups, suggesting that other plasmid genes are spreading in K. pneumoniae isolates, which can coharbor and spread different carbapenemases simultaneously.

Investigation of genotyping and phenotyping characteristics of carbapenem-resistant Klebsiella pneumoniae isolates.

Klebsiella pneumoniae (K. pneumoniae) is a major cause of healthcare-associated infections and plays a prominent role in the widespread antibiotic resistance crisis. Accurate identification of carbapenemases is essential to facilitate effective antibiotic treatment and reduce transmission of K. pneumoniae. This study aimed to detect carbapenemase production in carbapenem-resistant K. pneumoniae strains using phenotypic and genotypic methods. A total of 67 carbapenem-resistant K. pneumoniae strains obtained from various clinical samples were utilized for identification and antimicrobial susceptibility by the Vitek 2 Compact system (Biomerieux, France). Carbapenemase production was determined by using the Polymerase chain reaction, Blue-carba test (BCT) and Carbapenem inactivation method (CIM). Out of the isolates, 59 (88.1%) were positive bla OXA-48, 16 (23.9%) bla IMP, and five (7.5%) were positive bla NDM. No bla KPC genes were detected. The CIM identified 62 (92.5%), BCT identified 63 (94%) of PCR-positive isolates. The sensitivity and specificity of the BCT and the CIM were determined to be 96.7%, 40%, and 96.7%, 25% respectively. The bla OXA-48 gene was found to be the most prevalent in K. pneumoniae isolates. Early identification of carbapenem resistance plays a vital role in designing effective infection control strategies and mitigating the emergence and transmission of carbapenem resistance, thus reducing healthcare-associated infections.

Genetic characterization of virulence and extended spectrum β-lactamase producing genes of Klebsiella pneumoniae isolated from bovine milk.

Mastitis associated Klebsiella pneumoniae species were isolated from bovine milk to characterize virulence genes (wabG and kfuBC) and extended spectrum β-lactamase (ESBL) genes (blaCTX-M-1, blaCTX-M-2, blaCTX-M-9, blaTEM, blaSHV and blaOXA). A total number of 325 bovine milk samples (195 raw and 130 mastitic milk specimens) collected from Banaskantha, a milk-shed district of Gujarat, India, were included in the study. A total number of 27 K. pneumoniae isolates were recovered, consisting of 17 (62.96%) isolates from raw milk and 10 (37.03%) isolates from mastitic milk samples, giving an overall prevalence of 8.31%. Antibiotic sensitivity patterns revealed that 20 out of 27 isolates were found to be multi-drug resistant. Based on combination disc diffusion test and HiCrome ESBL agar method, 20 (74.07%) and 25 (92.59%) isolates were detected as ESBL producers, respectively. Among virulence genes studied, presence of wabG (25/27; 92.59%) was higher than kfuBC (5/27; 18.51%). Beta-lactamase genes viz., blaSHV, blaTEM and blaCTX-M-1 were detected in 23/27 (85.18%), 3/27 (11.11%) and 2/27 (7.40%) of isolates, respectively; while, none of the isolates was found to be positive for blaCTX-M-9 and blaOXA-1 genes. Outcome of the study provided an insight into virulence genes and ESBL producing K. pneumoniae isolated from bovine milk samples in India.

Prevalence and molecular characterization of Multidrug-Resistant ESBL-Producing E. coli in commercial poultry

Background: Rural poultry farmers are gradually changing from the backyard poultry production to intensive production, which made poultry more vulnerable to diseases and lead to indiscriminate use of antimicrobials in poultry production. As per OIE, FAO and WHO, multiple spread antimicrobial resistant pathogenic bacteria are a serious global human and animal health problem. Hence the study has been carried out to know the antimicrobial resistance status of poultry in Tirunelveli, Tamil Nadu, India. Methods: The study was aimed to find the occurrence of extended spectrum beta lactamases (ESBLs) producing E. coli from poultry origin. Caecum samples from the broiler (n=180), desi chicken (n=180) and Japanese quail (n=180) were processed for the isolation and phenotypic identification of ESBL E. coli. The isolates were tested for antimicrobial susceptibility test and characterization of ESBL and virulence genes done by PCR. Result: On phenotypic confirmation of ESBL producing E. coli by combined disk diffusion test (CDDT), a total of 9.63% samples were positive for extended spectrum beta lactamase producer (ESBL). Multi drug resistance (MDR) was observed in 38.23% of the broiler isolates, 27.27% and 57.14% in desi chicken and Japanese quail isolates, respectively. All the phenotypically confirmed ESBL producing E. coli isolates (n=52) were positive for uspA gene by PCR confirming the isolates as E. coli. The overall presence of the blaTEM gene was 57.69%, with broiler isolates having the highest prevalence of 67.47%, followed by desi chicken 36.36% and Japanese quail 42.85%. In contrast, the blaSHV gene was found in only 17.64% of the broiler isolates, but none were positive for the blaCTXM and blaOXA-1 gene.

Cross-talk of MLST and transcriptome unveiling antibiotic resistance mechanism of carbapenem resistance Acinetobacter baumannii clinical strains isolated in Guiyang, China.

Acinetobacter baumannii (A. baumannii) is an important opportunistic pathogen causing nosocomial infection in the clinic. The occurrence rate of antibiotic resistance is increasing year by year, resulting in a highly serious situation of bacterial resistance. To better understand the local epidemiology of multidrug-resistant A. baumannii, an investigation was conducted on the antibiotic resistance of different types of A. baumannii and its relationship with the genes of A. baumannii. Furthermore, the molecular mechanism underlying antibiotic resistance in A. baumannii was investigated through transcriptome analysis. These results showed that a total of 9 STs were detected. It was found that 99% of the strains isolated in the hospital belonged to the same STs, and the clone complex CC208 was widely distributed in various departments and all kinds of samples. Furthermore, these A. baumannii strains showed high resistance to ertapenem, biapenem, meropenem, and imipenem, among which the resistance to ertapenem was the strongest. The detection rate of bla OXA-51 gene in these carbapenem resistance A. baumannii (CRAB) reached 100%; Additionally, the transcriptome results showed that the resistance genes were up-regulated in resistance strains, and these genes involved in biofilm formation, efflux pumps, peptidoglycan biosynthesis, and chaperonin synthesis. These results suggest that the CC208 STs were the main clonal complex, and showed high carbapenem antibiotic resistance. All these resistant strains were distributed in various departments, but most of them were distributed in intensive care units (ICU). The bla OXA-23 was the main antibiotic resistance genotype; In summary, the epidemic trend of clinical A. baumannii in Guiyang, China was analyzed from the molecular level, and the resistance mechanism of A. baumannii to carbapenem antibiotics was analyzed with transcriptome, which provided a theoretical basis for better control of A. baumannii.

Molecular Characterization of bla OXA-51 Gene among Acinetobacter baumannii Isolates in Babylon Province

Molecular Characterization of bla OXA-51 Gene among Acinetobacter baumannii Isolates in Babylon Province

A Food Poisoning Caused by Salmonella Enterica (S. Enteritidis) ST11 Carrying Multi-Antimicrobial Resistance Genes in 2019, China.

This study was to identify and analyze the pathogen responsible for food poisoning in a tourist group traveling from Macao to Zhuhai. Samples were obtained from 27 patients of 96 cases, as well as samples of contaminated food in Macau. The collected samples were subjected to serological identification, drug sensitivity analysis, drug resistance gene identification, virulence factor analysis, and tracing. Twenty-six isolates and the salad isolate were S. enteritidis ST11. Isolates from patients were exhibited significant resistance to Penicillin AMP (Ampicillin) and quinolones NAL (Nalidixic acid). Among these isolates, 21 strains were resistant to two or more antibiotics, indicating the multi-drug resistance (MDR). Genomic characteristics and phylogenetic analysis were performed on 9 of the isolates using whole genome sequencing (WGS). The analysis revealed that the resistance to AMP and NAL was primarily caused by a gryA mutation D87Y (9/9, 100%), and the presence of beta-lactam resistance genes blaOXA-1 (1/9, 11.11%), blaTEM-141 (1/9, 11.11%), and blaTEM-1B (8/9, 88.89%). It was also found a strains isolated from patients had two resistance genes to quinolones or beta-lactam drugs (1/8, 12.5%), respectively. The strains were found to possess 165 virulence genes, one adherence class virulence factor, one invasion class virulence factor and various pathogenicity islands, including SPI-1, SPI-2, SPI-3, SPI-4, SPI-5, SPI-9, SPI-10, SPI-13, SPI-14, SPI-15, SGI 1, CS54_island, and C63PI-1. Additionally, the virulence plasmids were detected, including IncFIB(s)-IncFII(s)-IncX1 (55.56%), IncFIB(s)-IncFII(s) (33.33%), and IncFIB(s)-IncFII(s)-IncHI2-IncHI2A (11.11%). PFGE (Pulsed Field Gel Electrophoresis) and phylogenetic tree analysis revealed a high degree of similarity between Salmonella isolates from patients and food samples from Macao. This study identified Salmonella enterica ST11 as the cause of the food poisoning outbreak. The findings highlight the importance of phenotypic characterization and next-generation sequencing (NGS) tools in epidemiological studies and emphasize the potential risk of a new emerging multi-antibiotic ST11 clone for S. enteritidis.

Detection Sequencing NDM and blaOXA Genes in Metallo-$\beta$-Lactamase Producing Klebsiella Pneumoniae

The prevalence of Carbapenem-resistance in Enterobacteriaceae is rising worldwide and poses a treatment challenge for healthcare facilities. This study aims to detect a sequence of New Delhi metallo- -lactamase (NDM) and bla OXA-48 gene in metalo-beta-lactamase-producing Klebsiella pneumoniae isolated from a few hospitals in the city of Baghdad. 74 Klebsiella pneumoniae were isolated from 320 clinical samples that were routinely submitted to the diagnostic laboratory of the chosen hospital. These samples included sputum, tissue swabs, folly tips, urine, ear swabs, bloodstream, pus, wound swabs, endotracheal tubes, and body fluids. In this study, 74 isolates were examined for expression of carbapenemase by phenotyping method. The modified Hodge Test (MHT) is utilized for phenotypic detection. MHT was positive for 24 carbapenem-resistant Klebsiella pneumoniae. Genotyping was accomplished by using polymerase chain reaction (PCR) to amplify target genes by employing particular primers. The NDM gene was detected in 19/24 isolates, and the blaOXA-48 gene was detected in 5/24 isolates. The presence of bla NDM and the dangerously high frequency of MBL in the Klebsiella pneumoniae strain are both concerning, and it has been demonstrated to be challenging to treat and inhibit infection.

Identification of Multiple Drug-Resistance Genes in Clinical Isolates of Acinetobacter baumannii

Around the world, Acinetobacter baumannii is a nosocomial pathogen that accounts for 80% of hospitalized patient infections. This opportunistic bacterium can cause a wide range of infections, including skin and soft tissue infections, meningitis, pneumonia acquired on a ventilator, urinary tract infections, and bacteremia, all of which have a high death rate of almost 63.3%. Finding multidrug-resistant genes in the clinical isolates of A. baumannii was the goal of this study. Twenty-four (24) A. baumannii clinical isolates were obtained from the Federal Teaching Hospital in Gombe, Nigeria, and subcultured on MacConkey agar for eighteen to twenty-four hours at 37 ˚C. The isolates were identified using traditional biochemical testing, morphology, and cultural traits. The VITEK was then used to validate the identification. Twenty of the 24 isolates had been identified as A. baumannii. The Kirby Bauer method and CLSI recommendations were utilized to determine the antibiotic susceptibility of the A. baumannii isolates. Polymerase Chain Reaction was used to identify the genes that were resistant to many drugs. According to the data, fifteen (15) A. baummanii isolates, or 75% of the total, were likely multidrug resistant. The presence of the BlaNDM-1 gene in eight isolates, the BlaOXA23 gene in six isolates, and the BlaVIM gene in just four isolates was confirmed by molecular detection of the MDR genes from these isolates. These results show that a significant portion of the isolates of A. baumannii carried genes resistant to many drugs, which could be the root cause of any infection treatment failure caused by this organism.

Molecular characterization of the multi-drug resistant Myroides odoratimimus isolates: a whole genome sequence-based study to confirm carbapenem resistance.

The bacteria belonging to the Myroides genus are opportunistic pathogens causing community or hospital-acquired infections that result in treatment failure due to antibiotic resistance. This study aimed to investigate molecular mechanisms of antibiotic resistance, clonal relatedness, and the biofilm forming capacity of the 51 multi-drug resistant Myroides odoratimimus. All isolates were screened for blaKPC, blaOXA, blaVIM, blaIMP, blaMUS, blaTUS, blaNDM, and blaB genes by using PCR amplification. Whole genome sequencing (WGS) was applied on three randomly selected isolates for further investigation of antibiotic resistance mechanisms. Clonal relatedness was analyzed by Pulsed-field gel electrophoresis (PFGE) and the microtiter plate method was used to demonstrate biofilm formation. All isolates were positive for biofilm formation. PCR analysis resulted in a positive for only the blaMUS-1 gene. WGS identified blaMUS-1, erm(F), ere(D), tet(X), and sul2 genes in all strains tested. Moreover, the genomic analyses of three strains revealed that genomes contained a large number of virulence factors (VFs). PFGE yielded a clustering rate of 96%. High clonal relatedness, biofilm formation, and multi-drug resistance properties may lead to the predominance of these opportunistic pathogens in hospital environments and make them cause nosocomial infections.

Occurrence of Carbapenem-Resistant Enterobacteriaceae (Cre) Abhorring Bla Imp, Bla Kpc And Bla Oxa-48 Genes Recovered From Ready -To- Dispose Poultry Wastes In Osogbo, Osun State

The uncontrolled use of antimicrobials in animal husbandry such as poultry for prophylaxis reasons is to increase output for monetary gains which have led to several acquired community infections with high mortality and morbidity rates. This study is however aimed at investigating the occurrence, prevalence, and molecular detection of carbapenemase genes of carbapenem-resistant Enterobacteriaceae (CRE) bacteria isolated from poultry liters in Osogbo, Osun State Nigeria. Twenty ready-to-pack poultry waste samples were plated for the isolation of Enterobacteriaceae on MacConkey and Brilliance Escherichia coli agar. Disc diffusion method was employed for screening carbapenem resistant isolates while resistant genes were detected using carbapenem resistant gene primers. Forty-six Enterobacteriaeceae were isolated namely: Kluyvera ascorbate (28.3%), Klebsiella oxytoca (10.9%), Citrobacter koseri (8.7%), Klebsiella aereogenes, Raoultell (Klebsiella) planticola, Serratia nematodipila (6.5%), Trabulsiella laguamensis, Salmonella spp. (diarizonae), Proteus vulgaris, Citrobacter farmeri (4.3%), of which Edwardsiella tarda, Providencia rustigianii, Citrobacter freundii, Enterobacter cloacae, Cedecea lapagei, Serratia liquefaciens and Dickeyachry santhemi was (2.2%) respectively. 52.2% of the isolates were carbapenem resistant while 92% of the CRE had bla IMP genes. Only one CRE (Trabulsiella guamensis) was positive to bla KPC gene while four 16.6% of the isolates namely: Citrobacter koseri, Raoultell (Klebsiella) planticola, Serratia nematodipila, Citrobacter freundiu and Citrobacter koseri were positive to blaOXA-48 gene. Therefore, this study infers the high prevalence of CRE isolates in poultry litters as a public health concern for the indiscrimate use of carbapenem.
 Stamford Journal of Microbiology, 2023. Vol. 13, Issue 1, p. 15-20