Jundishapur Journal of Microbiology
Volume:14 Issue: 11, Nov 2021

The quick diagnosis and early initiation of antibiotic therapy in bacteria-induced infections is of paramount importance. Accordingly, the rapid identification of the causative agent, the short-term results of antibiotic sensitivity, the selection and use of right antibiotics for treatment further highlights the significance of this issue.

This study aimed to develop a new susceptibility testing method to provide rapid results in Escherichia coli clinical isolates and report the antibiotic susceptibility test results to clinicians in a short period.

In the study, one hundred and ten E. coli clinical isolates were tested. In this regard, antibiotics recommended by the "Clinical and Laboratory Standards Institute (CLSI)" for testing the sensitivity of E. coli isolates, including amoxicillin-clavulanate, cefixime, ceftriaxone, ertapenem, ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole, and nitrofurantoin were tested. For quality control, E. coli ATCC25922, E. coli ATCC35218, Staphylococcus aureus ATCC29213, and E. coli 13846NTCC strains were used. The broth microdilution method recommended by CLSI was used as the reference method. Minimum inhibitory concentration values were determined, and antimicrobial susceptibilities were then determined according to the “European Committee on Antimicrobial Susceptibility Testing (EUCAST)” criteria. In the next phase, the results of the resazurin microplate method (RMM) were compared.

The comparison of the RMM developed in the present study with the reference method revealed that the calculated essential agreement ratios for eight antibiotics varied from 82.72 to 100%, and the categorical agreement values ranged from 95.45 to100%.

According to the findings, the RMM results were highly in agreement with the results of the reference method. RMM allows the detection of antibiotic susceptibility quickly (e.g., within 5 hours) as such it is preferred, especially for laboratories with limited facilities. However, further multi-center studies are recommended to use this method in routine laboratories.

The knowledge of antibody’s significance and frequency in patients cured of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is extremely limited.

This study aimed to evaluate anti-SARS-CoV-2 IgG antibodies in patients exposed to SARS-CoV-2.

Healthcare professionals infected with SARS-CoV-2 were enrolled in this study. The levels of anti-SARS-CoV-2 IgG antibodies were detected 15 days after the onset of symptoms and five months later.

A total of 167 patients with coronavirus disease 2019 (COVID-19) were evaluated, including 119 (71.3%) females and 48 (28.7%) males. Of the 88 polymerase chain reaction (PCR)-positive patients, 55 (62.5%) had IgG-positive antibodies, and of the 79 reverse transcriptase (RT)-PCR-negative patients, 12 (16.9%) had IgG-positive antibodies. Out of 23 anosmia cases, 19 (82.6%) had positive antibodies. There was a significant relationship between anosmia and positive antibody (P  =  0.001), but there was no correlation between antibody titers and gender and other disease symptoms. Immortally, 63 (94%) cases demonstrated high levels of anti-SARS-CoV-2 IgG antibodies after five months of infection. Moreover, 6.5% (N  =  11) of the total population were re-infected with COVID-19 six months later.

Overall, anti-SARS-CoV-2 IgG antibodies detection may be an appropriate method to identify suspected patients with a negative RT-PCR test. Antibodies can remain high in most infected patients for up to five months after infection. Moreover, anosmia seems to be a valuable diagnostic factor, and the healthcare system should implement isolation measures for patients with anosmia.

Salmonella is one of the main foodborne bacterial pathogens, causing diseases and death. The study used reverse transcription loop-mediated isothermal amplification (RT-LAMP) to detect Salmonella.

To design six primers and detect Salmonella using RT-LAMP to facilitate the rapid detection of pathogenic bacteria in food.

We designed six primers based on the gene coding sequences of inv A, specific to Salmonella. Each reaction solution contained 6.0 mM MgSO4, 1 M betaine, 1.6 mM dNTPs, 160 U/mL Bst DNA polymerase, 0.2 μM of both external primers, 0.8 μM of both internal primers, and 0.2 μM of both loop primers. The reaction temperature was 65°C.

Our amplified products were separated by 2% agarose gel electrophoresis. The detection limit was 10 CFU per reaction.

RT-LAMP exhibited the same accuracy as the GB assay in detecting Salmonella in foods. RT-LAMP was highly specific and sensitive; hence, it may serve as an effective tool in detecting Salmonella.

Due to the overlapping clinical characteristics of respiratory tract infections (RTI)s and unavailability of appropriate diagnostic techniques, the diagnosis of RTIs is arguing. The aim of study was to prompt diagnosis of RTI using commercial multiplex real time PCR.

The survey undertook over a period of 2 years (2019-2020), on 144 flu-negative immunocompetent outpatients. Respiratory samples were examined by multiplex PCR assays.

Study population consisted of females 77 (53.5%) and males 67 (46.5%). The mean age was 42.8 ± 23.7 SD years. Thirty-one (21.5%) of patients infected with only one viral or bacterial infections. Eighty-two (57%) were infected with more than one pathogen. Ninety-five (37%) and 161 (62%) tests were positive for bacterial and viral pathogens, respectively. Community-acquired pneumonia (CAP) and atypical CAP pathogens included 17% and 10% of respiratory specimens, respectively. The predominant pathogens consisted of Human Herpes Virus 7 (HHV-7), 38 (15.5%); Epstein-Barr Virus (EBV), 34 (13.8%); Mycoplasma pneumoniae, 24 (9.8%) and Human Herpes Virus 6 (HHV-6), 21 (8.5%). There were associations between pathogen finding and special age categories. Fever, cough, dyspnea and hemoptysis were associated with certain pathogens identification. There was not substantial difference between viral and bacterial Ct in relation with genders, age group and presence of comorbidities.

Multiplex diagnostic assays significantly increased the rate of appropriate diagnosis of respiratory pathogens. However, further investigation needed for finding the significance of non-respiratory viruses in respiratory specimens of immunocompetent symptomatic patients.

In recent years, the widespread use of antibiotics has resulted in increased rates of antibiotic resistance (ABR). Pseudomonas aeruginosa is one of the most important opportunistic pathogens causing hospital-acquired infections. P. aeruginosa has continuously increased resistance to commonly used clinical antimicrobial drugs, bringing great difficulties to clinical treatment.

This retrospective study investigated the epidemiological characteristics of P. aeruginosa and changes in ABR over a 5-year period at a hospital in Shandong Province, China.

Pseudomonas aeruginosa strains were collected from 2015 to 2019. The antimicrobial susceptibility testing employed the Kirby-Bauer disk diffusion method and the broth microdilution method (VITEK-2 compact system), according to the guidelines by the Clinical and Laboratory Standards Institute. Data were analyzed using WHONET 5.6 and SPSS V. 21.0 software.

A total of 3,324 P. aeruginosa strains were isolated from clinical specimens (604, 631, 700, 595, and 794 strains from 2015 to 2019, respectively). The highest P. aeruginosa detection rates were from respiratory tract specimens (72.54%). The highest resistance was seen in aztreonam, followed by ciprofloxacin, levofloxacin, and imipenem. The isolation rates for carbapenem-resistant P. aeruginosa (CRPA) and multidrug-resistant P. aeruginosa (MDRPA) ranged from 15.21 - 18.38% and 17.31 - 27.31%, respectively. Also, the isolation rates for extensively drug-resistant P. aeruginosa (XDRPA) ranged from 1.86 - 3.52%.

The main sources of the P. aeruginosa isolates were older adult patients with chronic respiratory diseases. The isolation rates for CRPA, MDRPA, and XDRPA strains decreased over the 5-year period. However, the drug resistance situation remains a serious concern. Hence, continued infection control and antimicrobial stewardship and basic and clinical research on bacterial resistance are essential.

Hemodialysis patients are more prone to Hepatitis C Virus (HCV) infection due to the need for long-term hemodialysis and blood transfusions.

The present study aimed to determine the HCV infection burden, viral load, and genotype pattern in hemodialysis patients referred to a research center from 2011 to 2018.

Among 131 hemodialysis patients with suspected HCV infection, referred to Prof. Alborzi Clinical Microbiology Research Center, Shiraz, Iran, from 2011 to 2018, the HCV rate was assessed with the enzyme-linked immunosorbent assay and the HCV RNA load and genotypes by one-step TaqMan real-time PCR.

The prevalence of HCV-Ab positivity was 29% among hemodialysis patients, of whom 21 (57%) were HCV RNA-positive. In the rest of the hemodialysis patients who were HCV-Ab-negative, the HCV RNA was detected in five (12%) patients. Genotype 3 (Gt-3) was the most prevalent one detected in 50% of the patients whose genotypes were determined. Also, the HCV viral load in HCV-seropositive patients was generally higher than that in HCV-seronegative ones.

This study showed that high HCV infection and different genotype patterns among hemodialysis patients compared to the general population are the main predictors of HCV infection, which indicates healthcare facility transmission because of inappropriate infection management practices.