Jundishapur Journal of Microbiology
Year:2020 | Volume:13 | Issue:4|Papers Count:6

Background: New Delhi metallo-beta-lactamase 1 (NDM-1) is considered to be an important factor of antimicrobial resistance in Enterobacteriaceae. In China, the blaNDM-1 gene has been mostly detected in carbapenem-resistant Acinetobacter spp. but is less reported in Enterobacteriaceae and more rarely found in E. cloacae. Objectives: This study explored the genetic features of the blaNDM-1 gene of E. cloacae and a blaNDM-1knockout mutant was constructed using Red homologous recombination. In addition, the effect of the knockout on antimicrobial resistance, growth ability, and in vitro competitiveness was investigated. Methods: The upstream and downstream structures of the blaNDM-1 gene were analyzed in ten E. cloacae isolates using primer walking and PCR mapping. A blaNDM-1 knockout mutant was constructed through Red homologous recombination and verified by PCR, RT-qPCR, and sequencing. The antimicrobial susceptibility, growth curves, and in vitro growth competitiveness were compared between the blaNDM-1 knockout mutant and the parental strain. Results: All E. cloacae study isolates except for strain T10, contained an identical blaNDM-1 gene structure. The
ISAba125 truncated by ISEc33 element and the bleo followed by a
trpF and ISSen4 was located immediately upstream and downstream of T1-T9 strains. However, the
ISAba125 and the bleo followed by a
trpF were located immediately upstream and downstream, respectively, in the T10 strain. PCR, RT-qPCR, and DNA sequencing analyses showed that the blaNDM-1 knockout mutant was successfully constructed. The blaNDM-1 knockout mutant and the parental strain exhibited similar resistance patterns to penicillin, cephalosporins, aminoglycosides, tetracycline, and quinolones. Both strains displayed similar growth curves in Luria Broth. The competition index (CI), defined as the knockout mutant/parental strain ratio was 0. 69 in the competition experiment in vitro. Conclusions: The DNA regions upstream and downstream of the blaNDM-1 gene often contained insertion sequences and elements. Red homologous recombination was successfully used to knock out blaNDM-1 in E. cloacae, which allowed us to decipher the links between this gene, antimicrobial resistance, and bacterial growth competitiveness.

Introduction: Fungal infections infect billions of people annually around the world, and invasive types with a high mortality rate are commonly associated with primary immunodeficiencies (PIDs), such as autosomal dominant hyper-immunoglobulin (Ig)E syndrome (AD-HIES), or deficiency of caspase recruitment domain-containing protein 9 (CARD9). Patients with CARD9, which is also associated with invasive fungal infection (such as meningitis) and deep dermatophytosis. The symptoms of CARD9 deficiency usually start at early childhood, and it is essential to diagnose and treat the disease appropriately to minimize infections and prevent mortality. Since CARD9 deficiency is a newly-introduced disease, investigation of the different aspects of this disease has been the focus of several studies. Case Presentation: We present a case with recurrent fungal infections and abdominal mass, and the result of his gene sequence indicates aCARD9deficiency. Interestingly, the patient hadno serious complications until the age of 14; however, theCARD9deficiency was a hereditary disorder. Surprisingly, the size of the abdominal mass in the patient was controlled by antifungal treatment. Conclusions: The present study indicates that a deficiency of CARD9 can be considered one of the possible causes of abdominal mass that can guide physicians toward proper diagnosis and treatment.

Background: Acinetobacter baumannii is one of the major bacteria causing nosocomial infections. The emergence of multidrugresistant (MDR) isolates causes morbidity and mortality and lead to financial burdens for patients and public health systems. Objectives: Regarding the use of ciprofloxacin and increase of ciprofloxacin resistance, this study was aimed to investigate the role of the efflux pump and mutations in gyrA and parC genes as the mechanisms of ciprofloxacin-resistance. Methods: This study was conducted on 55 strains of A. baumannii isolated from the patients hospitalized in Milad Hospital, Tehran. The isolates were identified by biochemical tests, and their antibiotic susceptibility was assessed by the disc diffusion method. To investigate the role of the efflux pump, minimum inhibitory concentration (MIC) of ciprofloxacin was determined in the presence and absence of the carbonyl cyanide m-chlorophenyl hydrazone (CCCP) inhibitor. The PCR was used for amplification of gyrA, and parC genes and sequencing of its products was carried out to track the mutations. Results: The highest and lowest antibiotic resistance were observed in ciprofloxacin (100%) and tobramycin (52. 7%), respectively. Moreover, 96% of the A. baumannii isolates exhibited MDR. Five percent of strains showed 4-fold MIC reduction after the use of the inhibitor and were reported as the strains with high activity effluxpump. In 100% of the isolates, gyrA and parC genes were detected, and only one mutation was observed in parC and gyrA genes in the studied isolates that altered amino acid type. Conclusions: Reduction in MIC in the presence of an efflux pump inhibitor confirmed its role in enhancing the resistance to ciprofloxacin insomeisolates. The results of this study also revealednosignificant relationship between the ciprofloxacin resistance of the studied isolates and mutation in the encoding region of parC and gyrA genes. Thus, the significance of other mechanisms, such as the expression of genes encoding efflux pump proteins, should not be neglected.

Background: Colistin is the last-resort antibiotic available to date against Multiple-drug-resistant (MDR) bacteria, particularly carbapenem-resistant Enterobacteriaceae (CRE) harboring the NDM 1 and KPC 2 genes. Objectives: The current study was designed to investigate extended-spectrum -lactamase (ESBL) production, colistin resistance, and the presence of mcr-1 in Klebsiella pneumoniae isolated from urine samples. Methods: A total of 298 clinical isolates of K. pneumoniae were collected for seven months in 2017 from the main labs of three government tertiary care hospitals in Pakistan. The ESBL activity of the isolates was assessed by the Double Disc Synergy test (DDST). All the ESBL-producing isolates were phenotypically screened for colistin resistance by dilution methods. Colistin-resistant isolates were subjected to PCR for mcr-1 detection. The confirmation was done by the Sanger sequencing method. Results: Out of 298 K. pneumoniae isolates, 35 (11. 7%) isolates showed ESBL activity. They were phenotypically screened for colistin resistance. Four (11. 4%) colistin-resistant isolates out of 35 (11. 7%) showed the minimum inhibitory concentrations (MICs) ranging from 4 mg/L to 8 mg/L. The mcr-1 gene was detected in all four colistin-resistant isolates via specific primers/PCR and confirmed by Sanger sequencing, showing 99% sequence similarity with the mcr-1 gene in GenBank. The sequence was submitted to NCBI GenBank, and an accession number was assigned. Conclusions: The presence of the mcr-1 gene in ESBL-producing bacteria isolated from human urine samples highlights the urgent need for surveillance studies on a larger scale to overcome the inappropriate use of colistin-containing formulations and prevent further spread of resistance to this antibiotic.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is known to be one of the most potentially pathogenic organisms in the world. Skin infections are one of the significant infections of S. aureus. Therefore, therapeutic constraints have challenged researchers to seek new strategies to produce new medicines. Antimicrobial peptides (AMPs) are a new generation of natural drugs with antimicrobial properties and high fatality potency. Oncorhyncin II AMP is a group of peptides with bacteriostatic activity and antimicrobial effect against Gram-positive and Gram-negative bacteria. Therefore, the development and promotion of antimicrobial peptides can be a new step in the treatment of skin infections due to bacterial resistant S. aureus in hospitals. Objectives: The objective of this study was to produce recombinant Oncorhyncin II protein and evaluate its antimicrobial effects on MRSA to determine the outcomes of the treatment. Methods: In this experimental study, the Oncorhyncin II Antimicrobial peptide was synthesized by the recombinant method. The effectiveness of this peptide was assessed by the minimum inhibitory concentration (MIC) test. The activity of recombinant protein against S. aureus was investigated using in vitro and in vivo experiments. Results: The effectiveness of this peptide obtained by the MIC test was 225  g/mL. The activity test confirmed the MIC test and showed that this antimicrobial peptide has been able to reduce MRSA cell growth. All mice infected with MRSA responded positively to the protein treatment. Conclusions: According to Oncorhyncin II antimicrobial peptide activity studies, this peptide, as a new generation of antibiotics, was expected to have positive outcomes in the improvement of S. aureus skin infections. Therefore, the results of the efficacy require further studies to be confirmed.

Context: The novel coronavirus disease (COVID-19) is one of the most threatening pandemics in history involving multiple organs, including the kidney. This study aimed to review the association of COVID-19 with renal involvement. Evidence Acquisition: International databases, including theWeb of Science, PubMed, Scopus, and Google Scholar, were searched for articles by April 1, 2020. Keywords were COVID-19, coronavirus disease, SARS-CoV-2, kidney, renal function, acute kidney injury, and acute renal failure, or a combination of them in title/abstracts. Results: There were a few studies concerning COVID-19 and renal failure due to the short time elapsed from the epidemic onset. The results showed that hematuria and proteinuria were common in patients with COVID-19. Conclusions: Patients with elevated creatinine are at risk of mortality two times more than patients with normal creatinine. Also, elevated BUN, proteinuria, and hematuria can increase the risk of mortality in patients with COVID-19 up to four times compared to patients with normal tests. Therefore, it is important to check creatinine, BUN, proteinuria, and hematuria in primary assessments. Generally, all routine measures for people affected with COVID-19 can be done for COVID-19 patients with acute renal failure until the current knowledge is changed. Chloroquine phosphate may improve the chance of treatment.