Extensive Drug Resistance Research Articles

Emergence of carbapenem-resistant Enterobacter hormaechei ST93 plasmids co-harbouring blaNDM-1, blaKPC-2, and mcr-9 in bloodstream infection

We isolated a strain of Enterobacter hormaechei, ECC2783, co-harbouring blaNDM-1, blaKPC-2 and mcr-9 plasmids from a bloodstream infection and investigated its biological features. The presence of carbapenemase genes and mcr-9 was confirmed by polymerase chain reaction amplification. Whole genome sequencing and genomic analysis were performed on ECC2783. Experiments assessing the conjugation and stability of plasmids carrying the carbapenemase gene were performed. We also performed a colistin resistance induction experiment and studied the fitness cost of transconjugants. ECC2783 has an extensive drug resistance phenotype. Multilocus sequence typing analysis results showed that ECC2783 belongs to sequence type 93. Bioinformatics analysis confirmed that ECC2783 has four plasmids, of which pECC2783_a, carrying mcr-9, is the IncHI2 type, and pECC2783_c, carrying blaNDM-1, is the IncX3 type. pECC2783_d, carrying blaKPC-2, is an unclassified type. We successfully obtained two transconjugants (J53/ECC2783_1, carrying blaNDM-1, and J53/ECC2783_2, carrying blaKPC-2 and blaNDM-1). There was no statistically significant difference in the relative growth rate between J53 and J53/ECC2783_2. For the first time, we isolated carbapenem-resistant E. hormaechei plasmids co-harbouring blaNDM-1, blaKPC-2, and mcr-9 from a patient with a blood stream infection. This isolate has a survival advantage in a hospital environment, and its clinical monitoring should be strengthened.

Correlation Between Antimicrobial Resistance And Virulence Genes In Klebsiella Pneumoniae Isolates From Egypt.

To genotypically assess the relationship between certain resistance and virulence determinants. The cross-sectional study was conducted at Kafrelsheikh University, Egypt, from March 2019 to May 2021, and comprised pathologicalsamples, like blood,sputum, urine, vaginalswabs and wound swabs, that had been taken from patients who had never received treatment. The sample were collected from Kafrelsheikh and Mansoura University hospitals, and Klebsiella pneumoniae isolates were obtained. Resistance and virulence determinants were tested phenotypically. Uniplex polymerase chain reaction was used to evaluate the presence of several resistance accompanied genes and virulence genes in the isolates. Disc diffusion method was used to assess the isolates' susceptibility in accordance with the Clinical and Laboratory Standards Institute criteria for identifying diverse resistance patterns. There were 23 isolatesfrom 16 patients. Of the tested isolates, 22(95.65%)showed drug resistance; 19(82.6%) had multidrug resistance, and 3(13.04%) had extensive drug resistance. There was no case of pan drug resistance. CTX-M-15, NDM, CTX-M-1, VIM-1 and qnr B genes were detected in 14(60.86%), 13(56.5%), 6(26.08%), 6(26.08%) and 6(26.08%) isolates, respectively. Moreover, 6(26.08%) isolates exhibited extended-spectrum β-lactamase producers, and 12(52.17%) ofsuch isolates contained both CTX-M-1 and CTX-M-15 genes, 6 and 33.3% contained CTX-M-1, CTX M-15 and fox genes. Type 3 fimbriae adhesin mrkD and mucoviscosity regulatory gene uge were found in the tested isolates. However, gene of iron uptake system kfu wasfound in 8(34.78%) isolates, and increased serum survival protein is and mucoviscosity accompanied gene magA were detected in 3(13.04%) isolates. A direct correlation was found among 5 from 8 Klebsiella pneumoniae virulence genes and antimicrobial resistance genes. There was a direct correlation between the existence of virulence factors and resistance to antimicrobials.

Escherichia coli B-Strains Are Intrinsically Resistant to Colistin and Not Suitable for Characterization and Identification of mcr Genes.

Antimicrobial resistance is an increasing threat to human and animal health. Due to the rise of multi-, extensive, and pandrug resistance, last resort antibiotics, such as colistin, are extremely important in human medicine. While the distribution of colistin resistance genes can be tracked through sequencing methods, phenotypic characterization of putative antimicrobial resistance (AMR) genes is still important to confirm the phenotype conferred by different genes. While heterologous expression of AMR genes (e.g., in Escherichia coli) is a common approach, so far, no standard methods for heterologous expression and characterization of mcr genes exist. E. coli B-strains, designed for optimum protein expression, are frequently utilized. Here, we report that four E. coli B-strains are intrinsically resistant to colistin (MIC 8-16 μg/mL). The three tested B-strains that encode T7 RNA polymerase show growth defects when transformed with empty or mcr-expressing pET17b plasmids and grown in the presence of IPTG; K-12 or B-strains without T7 RNA polymerase do not show these growth defects. E. coli SHuffle T7 express carrying empty pET17b also skips wells in colistin MIC assays in the presence of IPTG. These phenotypes could explain why B-strains were erroneously reported as colistin susceptible. Analysis of existing genome data identified one nonsynonymous change in each pmrA and pmrB in all four E. coli B-strains; the E121K change in PmrB has previously been linked to intrinsic colistin resistance. We conclude that E. coli B-strains are not appropriate heterologous expression hosts for identification and characterization of mcr genes. IMPORTANCE Given the rise in multidrug, extensive drug, and pandrug resistance in bacteria and the increasing use of colistin to treat human infections, occurrence of mcr genes threatens human health, and characterization of these resistance genes becomes more important. We show that three commonly used heterologous expression strains are intrinsically resistant to colistin. This is important because these strains have previously been used to characterize and identify new mobile colistin resistance (mcr) genes. We also show that expression plasmids (i.e., pET17b) without inserts cause cell viability defects when carried by B-strains with T7 RNA polymerase and grown in the presence of IPTG. Our findings are important as they will facilitate improved selection of heterologous strains and plasmid combinations for characterizing AMR genes, which will be particularly important with a shift to Culture-independent diagnostic tests where bacterial isolates become increasingly less available for characterization.

Current Sensitivity Pattern of Salmonella Species in Children Presenting at a Tertiary Care Hospital

Background: Enteric fever is a common and treatable pediatric bacterial infection, but emerging drug resistance has been a real challenge for treating physicians. Since 2016, Pakistan is facing the epidemic of Extensively drug resistant (XDR) salmonella typhi. Objective: To determine the clinical presentation and current pattern of sensitivity of salmonella species in children diagnosed with enteric fever. Study Design: Descriptive, Cross sectional Place and Duration of Study: Pediatric department of Dr. Ruth K. M. Pfau Civil Hospital Karachi, from July to December 2022. Methods: Medical records of patients 1 month to 12 years of age, diagnosed as enteric fever on positive blood culture for salmonella, were inducted into the study by non-probability convenient sampling. The clinical manifestations of patients and sensitivity and resistance patterns of salmonella were recorded. Data was analyzed using SPSS version 22. Results: A total of 140 children had enteric fever, out of which 60.7% were male. Mean age of the patients was 4.48+2.47 years. Most common symptom was fever in 140 (100%), followed by anorexia in 97 (69.2%) and abdominal pain in 70 (50%). Blood culture reports showed Extensive drug resistance in 105 (75%), Multi drug resistance in 3 (2.14%) and Non-resistance in 7 (5%). Salmonella Typhi isolates were sensitive to Carbapenems in 140 (100%), Azithromycin 139 (99.2%) and Piperacillin/Tazobactam in 60 (42.8%). Conclusion: XDR enteric fever is still the most common resistance pattern identified in admitted patients with enteric fever. Large scale public health measures and antibiotic stewardship are required to fight this disease. Keywords: Typhoid fever, Salmonella Typhi, Drug resistance, Infection, Epidemic

Epidemiological manifestations of tuberculosis infection in the Omsk region: dynamics and trends

Background. Tuberculosis (TB) infection remains relevant as one of the leading public health problems in Russia.The aim. To characterize the dynamics and trends of epidemiological manifestations of TB infection in the Omsk region.Materials and methods. An observational descriptive-evaluative epidemiological study was carried out in the Omsk region from 2009 to 2021. The data available in the Federal statistical observation forms NN 7, 8, and 33, and results of the bacteriological study of patients with respiratory TB were analyzed.Results. In the Omsk region, an improvement in the epidemiological situation was observed from 2009 to 2021. It was associated with a decrease in TB prevalence by 3.7 times (from 325.6 to 86.7), mortality – by 5.8 times (from 21.1 to 3.6), incidence – by 2.7 times (from 130.7 to 48.4 per 100,000). At the same time, proportion of microscopy/culture-positive patients infected with multidrug-resistant Mycobacterium tuberculosis strains increased from 9.2 to 29.8 % among all patients, and from 15.5 to 30.6 % among newly diagnosed patients. There was a trend towards an increase in the number of cases with primary extensive drug resistance of M. tuberculosis. The incidence of tuberculosis associated with HIV infection has increased 10 times and reached 15.6 per 100,000 population.Conclusions. In the Omsk region, there is a change in the structure of M. tuberculosis strains with a predominance of multiple and extensive drug resistance along with decrease in TB incidence and mortality. New approaches are needed to organize the system of epidemiological surveillance and control of TB infection.

Phylogenetic Groups and Antibiotic Resistance Characteristics of Uropathogenic Escherichia coli

Background:Different phylogenetic groups of uropathogenic Escherichia coli are associated with increased virulence and multidrug resistance, highlighting the importance of understanding the genetic characteristics of these isolates for effective treatment and prevention of UTIs. Genomic analysis was conducted on 100 Escherichia coli isolates obtained from multiple hospitals in Baghdad, Iraq, which showed extensive resistance to multiple drugs, including both multi-drug resistant (MDR) and extensively-drug resistant (XDR) isolates. Methodology: Antibiotic susceptibility was evaluated using the disc diffusion technique. PCR was used to test for the presence of phylogenetic groupings and to characterise antibiotic resistance genes. Results: Phylogroup F (36.66%) and Phylogroup C (23.33%) were the most common. Isolates of UPEC were found in every phylogroup, except for the six that were untypable. The study identified 54 out of 70 typed Escherichia coli isolates that belonged to phylogroups F (33/70) and C (21/70) as multidrug-resistant, with a high percentage (70.76%) of these isolates demonstrating extensive drug resistance (XDR). Based on the presence of particular genes or DNA, E. coli populations are classified into eight basic phylogenetic groups: A, B1, B2, C, D, E, F (belonging to E. coli sensu stricto), and clade I (belonging to Escherichia clade). Conclusion: Based on our findings, certain types of E. coli belonging to the phylogenetic group F are more common, more dangerous, and more resistant to antibiotics than others when it comes to UTIs.

Drug hypersensitivity in drug-resistant tuberculosis

ObjectiveTo evaluate drug resıstant tuberculosis patients who developed drug hypersensitivity to antituberculosis drug. MethodsThis was a retrospective study. The primary aim of the study is to determine the demographic and clinical characteristics of patients who develop drug hypersensitivity in drug resistant tuberculosis patients. The secondary aim of the study is to examine the treatment results. Demographic features, tuberculosis diagnostic indicator, clinical signs of developing hypersensitivity reaction, reaction time, and treatment were evaluated. ResultsA total of 25 patients were included in the study. The prevalence of hypersensitivity in drug resistance patients was 11.9%. Twelve (48%) of the cases were women. Mean age (mean ± SD) was 37.24 ± 14.44 years; early type hypersensitivity reaction in 13 (52%). Three patients were isoniazid resistant; 19 patients were multidrug-resistant (MDR); 2 patients were pre-extensive drug resistant (Pre-XDR), 1 patient was extensive drug resistance (XDR) tuberculosis. The most common skin findings were maculopapular eruption and urticaria. But also we had seen ısole angıodema, urtıcarıa and angıoedema, erythema multıforme, lıchenoıd drug eruptıon and drug rash with eosinophilia and systemic symptoms. In patients who developed a hypersensitivity reaction, the responsible agent was identified in 14 cases in total. Among the drugs, pyrazinamide, ethambutol, moxifloxacin, amikacin, para amino salicylic, prothionamide, and cycloserine are the responsible agents. When evaluated in terms of treatment results, 15 (60%) patients successfully completed the treatment. ConclusionOur study is the first study in the literature that evaluated the drug hypersensitivity in drug resıstance tuberculosis patients. Drug hypersensitivity that develops with tuberculosis treatment may lead to discontinuation or change in treatment. İt can cause treatment failure, drug resistance, relapse, and even death. In resistant tuberculosis, the already existing resistance pattern may become more difficult to treat. Success can be achieved with the right management in these patients who have few treatment options, more drug side effects, and high treatment failure rates. The established regimen should be curative and prevent recurrence.

Clinical characteristics and drug resistance profile of patients with endobronchial tuberculosis in South Korea: single-center experience.

Tuberculosis (TB) is a major infectious disease worldwide; there has been a significant increase in the number of elderly patients with TB, largely contributing to TB-related mortality. Although endobronchial tuberculosis (EBTB) is a unique form of pulmonary TB, available data on the clinical characteristics and drug susceptibility (DST) patterns of patients with EBTB are scarce. We evaluated the clinical characteristics of patients with EBTB in South Korea and the culturebased DST patterns of EBTB. Further, the DST patterns were compared between elderly (≥65 years) and young (<65 years) patients. We retrospectively reviewed data of patients with EBTB who had the results of DST and were diagnosed between January 2013 and December 2019 at a tertiary referral hospital in South Korea. Phenotypic DST of 15 first-line and second-line anti-TB drugs was performed using Mycobacterium tuberculosis isolates prior to treatment. Of the 230 patients with EBTB, 69% were in elderly patients (≥65 years). Any-resistance occurred in 24 patients (10.4%), while multi-drug resistance (MDR) and extensive drug resistance (XDR) were observed in six patients (2.6%). Compared to that of the elderly treatment-naïve patients, previously treated elderly patients had a significantly higher proportion of resistance to rifampin (14.3% vs. 2.2%; P=0.031), ethambutol (9.5% vs. 0.7%; P=0.046), and pyrazinamide (9.5% vs. 0.7%; P=0.046). Further, MDR/XDR was observed more frequently in the previously treated elderly patients than that in the treatment-naïve elderly patients (14.3% vs. 1.4%; P=0.017). A relatively small number of drug-resistant cases (5.6%) were observed in young patients. Elderly EBTB patients with previous Anti-tuberculous medications had a significantly higher proportion of drug-resistant TB. These patients should be carefully assessed using DST analysis before treatment.

The New Definition and Epidemiology of Extensive Drug Resistant Tuberculosis in 2020

The objective: to study the epidemiology and incidence of XDR tuberculosis given the updated definition.Subjects and Methods. The results of replies to the specialized inquiry by the Russian Ministry of Health about results of microbiological diagnostics and MTB drug susceptibility tests were studied. To assess the incidence of pre-extensive drug resistance, general population data were used, and for extensive drug resistance, data from 8 regions of Russia were used.Results. The incidence of pre-extensive drug resistance was 39,1% [95% CI 38,4–39,8] among tuberculosis cases with rifampicin resistance including 26,8% in new cases [95% CI 25,8–27,9]; among all cases receiving treatment for whom DST results were available, it made 20,2%, including primary resistance in 9,7%. The incidence of XDR among cases with pre-extensive drug resistance was 3,0% [95% uncertainty interval 1,8–5,3] for all cases, including primary resistance in 1,6% [95% uncertainty interval 0,2–5,7].Conclusion. Despite the low incidence of pre-extensive drug resistance, it is expected to increase primarily due to growing resistance to fluoroquinolones. Resistance to innovative drugs, in particular XDR, is not yet a serious problem.

Serotype distribution, trend of multidrug resistance and prevalence of β-lactamase resistance genes in human Salmonella isolates from clinical specimens in Guizhou, China.

Salmonella, one of the major causes of foodborne infections, can cause bacterial foodborne illness. We investigated the serotype distribution, multidrug resistance (MDR), and β-lactamase resistance genes of human Salmonella isolates collected from clinical specimens in Guizhou, China, between 2013 and 2018. A total of 363 Salmonella isolates were collected from clinical specimens at 17 surveillance hospitals. Twenty-four serotypes were identified by sliding agglutination test. S. Enteritidis (33.9%), Salmonella 4,[5],12:i:- (24.0%), S. Typhimurium (16.3%), S. London (6.3%), and S. Derby (3.9%) were the top five serotypes. In 2018, the most common serotype changed from S. Enteritidis to S. Typhimurium. Among the 363 Salmonella isolates, 97.5% of isolates were resistant to at least one class of antimicrobial agents. For cephalosporins, ceftriaxone had the highest resistance rate of 10.5%, and cefepime and cefoxitin were 8.0% and 2.2%, respectively. Three hundred and one (82.9%) Salmonella isolates showed MDR. Salmonella 4,[5],12:i:- had the highest MDR rate with 94.2%, followed by S. London (91.3%) and S. Typhimurium (88.1%). Multidrug resistance rates of Salmonella isolates in Guizhou from 2013 to 2017 increased from 75.8% to 86.7%. Sixteen isolates (4.4%) showed extensive drug resistance. One hundred thirty-four antimicrobial resistance patterns were found. Two hundred and forty-one (66.4%) isolates carried at least one β-lactamase resistance gene. The blaTEM gene (61.2%) was the most prevalent resistant gene in all Salmonella isolates, followed by the blaCTX-M gene (6.1%) and blaOXA-1 gene (4.1%). Our findings showed that the MDR rate of Salmonella isolates from Guizhou province increased year by year. Therefore, systematic and long-term surveillance on MDR Salmonella isolates from clinical patients should be further strengthened.

Epidemiological and Genetic Characteristics of Clinical Carbapenem-Resistant Pseudomonas aeruginosa Strains in Guangdong Province, China.

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a bacterial pathogen that may cause serious drug-resistant infections that are potentially fatal. To investigate the genetic characteristics of these organisms, we tested 416 P. aeruginosa strains recovered from 12 types of clinical samples collected in 29 different hospital wards in 10 hospitals in Guangdong Province, China, from 2017 to 2020. These strains were found to belong to 149 known sequence types (STs) and 72 novel STs, indicating that transmission of these strains involved multiple routes. A high rate of resistance to imipenem (89.4%) and meropenem (79.4%) and a high prevalence of pathogenic serotypes (76.4%) were observed among these strains. Six STs of global high-risk clones (HiRiCs) and a novel HiRiC strains, ST1971, which exhibited extensive drug resistance, were identified. Importantly, ST1971 HiRiC, which was unique in China, also exhibited high virulence, which alarmed the further surveillance on this highly virulent and highly resistant clone. Inactivation of the oprD gene and overexpression of efflux systems were found to be mainly responsible for carbapenem resistance in these strains; carriage of metallo-β-lactamase (MBL)-encoding genes was less common. Interestingly, frameshift mutations (49.0%) and introduction of a stop codon (22.4%) into the oprD genes were the major mechanisms of imipenem resistance. On the other hand, expression of the MexAB-OprM efflux pump and MBL-encoding genes were mechanisms of resistance in >70% of meropenem-resistant strains. The findings presented here provide insights into the development of effective strategies for control of worldwide dissemination of CRPA. IMPORTANCE Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a major concern in clinical settings worldwide, yet few genetic and epidemiological studies on CRPA strains have been performed in China. Here, we sequence and analyze the genomes of 416 P. aeruginosa strains from hospitals in China to elucidate the genetic, phenotypic, and transmission characteristics of CRPA strains and to identify the molecular signatures responsible for the observed increase in the prevalence of CRPA infections in China. These findings may provide new insight into the development of effective strategies for worldwide control of CRPA and minimize the occurrence of untreatable infections in clinical settings.

Design, synthesis, and biological evaluation of 1,2,4-triazole derivatives as potent antitubercular agents

Inhibition of mycobacterial membrane protein large 3 (MmpL3) thereby affecting the mycolic acid biosynthetic pathway has been proven to be an effective strategy for developing antitubercular drugs. Based on the X-ray crystal structure of MmpL3 inhibitor complexes, a series of novel 1,2,4-triazole derivatives were designed, synthesized and evaluated antitubercular activity against Mtb strain H37Rv. Comprehensive structure–activity relationship exploration resulted in the identification of compounds 21 and 28, which possess potent antitubercular activity against Mtb strain H37Rv [minimum inhibitory concentration (MIC) = 0.03–0.13 µg/mL] and the clinical isolates of multidrug resistance (MDR) and extensive drug resistance (XDR) tuberculosis (MIC = 0.06–1.0 µg/mL). Moreover, compounds 21 and 28 showed neglectable cytotoxicity (IC50 ≥ 32 µg/mL) to the mammalian Vero cells and favorable physicochemical and pharmacokinetic properties according to the in silico absorption, distribution, metabolism and excretion (ADME) prediction. Finally, the potential target of representative 1,2,4-triazole 28 was identified to be MmpL3 using a microscale thermophoresis (MST) assay.

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Drug-resistant Acinetobacter species isolated at the University Teaching Hospital, Lusaka, Zambia

Acinetobacter species have emerged as one of the leading causative agents of Hospital-Acquired Infections (HAIs). Acinetobacter baumannii, the most commonly isolated clinical subspecies among the Acinetobacter species, is known to cause a wide range of HAIs, with an increased risk of mortality ranging from 8% to 40% in hospitalized patients. This study aimed to evaluate the clinical significance of Acinetobacter species isolated from admitted patients, ward environmental surfaces and instruments at the University Teaching Hospital, (UTH) in Lusaka, Zambia.This was a facility-based cross-sectional study that involved collecting clinical samples (cerebrospinal fluid, sputum, pus swabs, blood culture, urine, synovial fluid, pericardial fluid, and pleural fluid) that were submitted to the Microbiology Laboratory at UTH as part of the routine diagnosis and patient care between July and December 2021. Environmental specimens were also collected from surfaces and equipment in contact with patients, such as beds, beddings, suction machines, ventilators, ward gowns and endotracheal tubes.Sixty Acinetobacter isolates were recovered, 40 (66.7%) from clinical specimens and 20 (33.3%) from environmental samples, respectively. Among the clinical isolates, the admission ward had the highest (21.7%; 95% CI: 10.9–32.4) while the main ICU had the least (1.7%; 95% CI: 0.0–5.0%); for environmental samples, the highest isolation was from taps (25%) and sinks (20%). Among the sixty Acinetobacter isolates, A. baumannii was the most prevalent subspecies (n = 43). Highest resistance was observed to tetracycline (98%; 95% CI: 94–100) and co-trimoxazole (70%; 95% CI: 58–82) while the lowest resistance was seen in imipenem (17%; 95% CI: 7.3–28.3), tobramycin (20%; 95%CI: 11.7–36) and cefotaxime (22%; 95% CI: 24–22). The AdeB gene (efflux pump) was detected in 82.5% of the clinical isolates. The frequency of clinical isolates that showed resistance to at least three classes of antibiotics (aminoglycosides, fluoroquinolones and sulphonamides) translated into being Multidrug-resistant (MDR) and Extensive drug resistance (XDR) in the clinical isolates was 75% (30/40) and 52.5% (21/30), respectively. These findings intimate the clinical significance of HAI Acinetobacter infections and need for continuous AMR surveillance to inform treatment guidelines and regular infection prevention processes.

Structure Based Discovery of Inhibitors of CYP125 and CYP142 from Mycobacterium tuberculosis.

Mycobacterium tuberculosis (Mtb) was responsible for approximately 1.6 million deaths in 2021. With the emergence of extensive drug resistance, novel therapeutic agents are urgently needed, and continued drug discovery efforts required. Host-derived lipids such as cholesterol not only support Mtb growth, but are also suspected to function in immunomodulation, with links to persistence and immune evasion. Mtb cytochrome P450 (CYP) enzymes facilitate key steps in lipid catabolism and thus present potential targets for inhibition. Here we present a series of compounds based on an ethyl 5-(pyridin-4-yl)-1H-indole-2-carboxylate pharmacophore which bind strongly to both Mtb cholesterol oxidases CYP125 and CYP142. Using a structure-guided approach, combined with biophysical characterization, compounds with micromolar range in-cell activity against clinically relevant drug-resistant isolates were obtained. These will incite further development of much-needed additional treatment options and provide routes to probe the role of CYP125 and CYP142 in Mtb pathogenesis.

Bacterial Profile and Antimicrobial Susceptibility Pattern in Septicemia Suspected Children and Available Treatment Options

OBJECTIVES Septicaemia (blood poisoning) is one of the chief sources of global morbidity and mortality in pediatric patients and presents with multidrug and extensive drug resistance. This study aims to detect the major causative agents, antimicrobial susceptibility patterns and associated factors of bacteraemia among pediatric patients.METHODOLOGY This retrospective cross-sectional study was done at National Medical Center, Karachi microbiology laboratory. Clinical specimens consist of blood. Blood samples were processed in BACTEC's automated blood culture system, and positive samples were sub-cultured on blood, Mac-Conkey. Final identification was done by API 20E and API 20NE (Biomerieux) and confirmed by MicroScan (Beckman coulter)®. The antimicrobial susceptibility was performed by using Bauer– Kirby disk diffusion method.RESULTS A total of 395 pediatric patients were taken in the study. Out of these patients, 226 (57.2 %) were female. The children with age 1-4 years were highly affected. Almost 50% were handled in emergency and transferred for admission. 36.2% of patients were exposed to intravenous devices. 89 (22.5%) patients had a history of prolonged use of antibiotics. Most patients with pneumonia presented with septicemia as a complication, and were detected by Klebsiella pneumonia (35.4%), Acinetobacter bauminii (25.3%) and Pseudomonas aeruginosa (20.3%). CONCLUSION The study revealed that gram-negative organisms are the predominant causative organisms of septicaemia. Antibiotic resistance to Carbapenem is gradually increased in the case of Acinetobacter bauminii and Escherichia coli. These issues can be overcome by early detection of microorganisms and establishing antibiotic stewardship.

Genetic characteristic of coexisting of mcr-1 and bla NDM-5 in Escherichia coli isolates from lesion-bearing animal organs.

The coexistence of mcr-1 and bla NDM-5 in the plasmid of Escherichia coli has been widely reported and such strains have been mainly isolated from animal and human feces. However, few reports have focused on the genetic diversity of mcr-1-carrying chromosomes and bla NDM-5-carrying plasmids in E. coli isolates from lesion-bearing animal organs. This study investigated the genetic characteristics of chromosome-mediated mcr-1 and plasmid-mediated bla NDM-5 in E. coli isolated from lesion-bearing animal organs. Nine mcr-1- and bla NDM-5-positive E. coli strains (MNPECs) showed extensive drug resistance (XDR). The predominant clonal complexes (CC) mainly belonged to CC156, CC10, and CC165 from the 56 MNEPCs (including nine strains in this study) retrieved from the literature. These strains were widely distributed in China, and originated from pig fecal samples, human stool/urine samples as well as intestinal contents of chicken. Two transconjugants harboring bla NDM-5 gene were also successfully obtained from two donors (J-8 and N-14) and this transfer increased the MIC for meropenem by 256 times. However, conjugative transfer of mcr-1 gene failed. Both J-8 and N-14 strains contained point mutations associated with quinolone resistance and more than three types of AMR genes, including the mcr-1 gene on the chromosome and the bla NDM-5 gene on the IncX3-type plasmid. The genetic structure of mcr-1 located on the chromosome was an intact Tn6330, and bla NDM-5-carrying IncX3-type plasmid was ISAb125-IS5-bla NDM-5-bleO-trpF-tat-cutA-IS26 gene cassette. Moreover, differences between chromosomes included additional partial sequence of phage integrated into host genome and the different genes associated with O-antigen synthesis.

In vitro activity of tetracycline analogs against multidrug-resistant and extensive drug resistance clinical isolates of Mycobacterium tuberculosis

BackgroundMultidrug-resistant tuberculosis (MDR-TB) has become a big threaten to global health. The current strategy for treatment of MDR-TB and extensive drug resistant tuberculosis (XDR-TB) is with low efficacy and high side effect. While new drug is fundamental for cure MDR-TB, repurposing the Food and Drug Administration (FDA)-approved drugs represents an alternative soluation with less cost. MethodsThe activity of 8 tetracycline-class antibiotics against mycobacterium tuberculosis (M.tb) were determined by Minimum Inhibitory Concentration (MIC) in vitro. A transposon M.smeg libraries was generated by using the Harm phage and then used to isolate the conditional growth mutants in doxycycline containing plate. Eleven mutants were isolated and genomic DNAs were extracted using the cetyltrimethyl ammonium bromide (CTAB) method and analyzed by whole genome sequencing. ResultsWe found that three of eight drugs efficiently inhibited mycobacteria growth under the peak plasma concentration in the human body. Further tests showed these three tetracycline analogs (demeclocycline, doxycycline and methacycline) had antimicrobial activity against seven clinical isolates, including MDR and XDR strains. Among them, Doxycycline had the lowest MICs in all mycobacteria strains tested in this study. By using a transposon library, we identify the insertion of transposon in two genes, porin and MshA, associatewith the resistant to doxycycline. ConclusionsOur findings show that tetracycline analogs such as doxycycline, has bactericidal activity against not only drug sensitive M.tb, but also clinical MDR and XDR strains, provided proof of concept to repurpose doxycycline to fight MDR-TB and XDR-TB. Further investigations are warranted to clarify the underlying mechanism and optimize the strategy in combination with other anti-TB drugs.

Resistance Pattern in Mostly Gram-negative Bacteria Causing Urinary Tract Infections.

The antimicrobial prescription in urinary tract infections (UTI) is driven by local data on its pathogenic spectrum and the resistance pattern exhibited by the disease-causing pathogens. We aimed to determine the bacteriological diversity of UTI causing pathogens and antimicrobial resistance in mostly gram-negative bacteria. This retrospective hospital-based cross-sectional study analyzed the culture and sensitivity reports of urine samples from a referral centre in the Aljouf region of Saudi Arabia. All the antibiograms from January 1, 2020, to December 31st 2020, were included. The bacterial identification and antimicrobial testing were carried out by the BD Phoenix system (BD Diagnostics, Sparks, MD, USA). Antimicrobial testing was performed as per the Clinical and Laboratory Standard Institute recommendations. Frequencies of multidrug- and extensive drug resistance were calculated. Of the 1334 non-duplicate urine samples received, 422 (31.6%) bacterial growths were observed. Of these, 383 (90.8%) and 39 (9.2%) were gram-negative and gram-positive bacterial isolations, respectively. E. coli 161 (38.1%), K. pneumoniae 97 (23.0%), and E. faecalis 18 (4.3%) were frequent aetiologies of UTI. 309 (80.7%) of gram-negative bacteria were multidrug-resistant including 88 (23.0%) extensively drug-resistant. Overall, a resistance rate of > 55 % to 1st through 4th generation cephalosporins was observed except for cefoxitin (43.7%). A resistance rate of 37.6% was observed towards carbapenems, with the lowest rate (34.0%) to meropenem. Multi-drug resistant gram-negative bacteria dominate the pathogenic spectrum of UTI in the region. A high resistance rate to cephalosporins and carbapenems exists in gram-negative organisms, causing UTI.

Study of Antibiotic Resistance in E. coli against Allopathic Drugs as Compared To Natural Herbs

The Rising Incidents of Antibiotic Resistance has been increasing at an exponential rate in recent years, and since it is often caused by rampant misuse of drugs such as Penicillin, many bacterial species such as E. coli have been able to mutate and gain Multi-Drug Resistance and Extended Drug Resistance (XDR) - to form what is otherwise known as Superbugs. The main purpose of the research is to investigate the efficacy of Allopathic Drugs as Compared to Natural herbs in treating pathogenic bacterial colonies, so as to find an alternative to reduce antibiotic resistance. Using experimental analysis, this study analysed the effectiveness of the allopathic drugs and natural herbs, in treating an E. coli culture. The experiment was carried out over a span of 14 days, with readings taken on every consecutive 2-day period. The efficacy was measured with respect to the zone of inhibition, and the results were compared for any form of resistance developed. The Allopathic drug, Azithromycin, as hypothesized was found to be the most effective in treating the E. coli culture, but a few resistant strains were observed. However, natural herbs like Tea tree oil were not far behind, and only a few colonies of E. coli showed resistance against them. Erythromycin and Garlic were not found to be as effective. This study answers the questions on alternatives to allopathic drugs and resistance to different substances. Further studies are however needed to establish the mechanism of resistance to these substances and to develop preventative measures