Jundishapur Journal of Microbiology
Volume:14 Issue: 5, May 2021

 Pseudomonas aeruginosa is a nosocomial pathogen, acquiring resistance to a wide range of antibiotics. The MexAB-OprM pump can lead to resistance in this organism. Thus, the study was conducted to determine the effect of chitosan and phenylalanine arginyl ß-naphthylamide (PaβN) on the expression of MexAB in isolated ciprofloxacin resistant P. aeruginosa.

 This study investigated the effect of an antibiotic combination on the MexABP. aeruginosa expression.

 A total of 30 ciprofloxacin-resistant isolates of P. aeruginosa were collected in this project. Then, chitosan nanoparticles were prepared using the ionic gelation method. Minimum inhibitory concentration (MIC) values were determined for ciprofloxacin, ciprofloxacin + PAßN, chitosan + ciprofloxacin, and chitosan + ciprofloxacin + PAßN using the micro-dilution method. Moreover, the expression level of MexAB genes was measured using real-time polymerase chain reaction.

 In total, 76.7% of the isolates were identified as multidrug resistant. A significant decrease in the MIC value was observed in groups treated with PAβN compared to those without PAβN. Moreover, the MIC value was significantly lower in the ciprofloxacin chitosan group than in groups without ciprofloxacin. Decreased MexA and MexB mRNA levels were observed in all antibiotic-treated strains compared to the ciprofloxacin-treated group.

 There is a significant relationship between the increased MexAB expression and resistance to ciprofloxacin (P-value < 0.05). One of the therapeutic concerns is multidrug resistant bacteria, which needs to be addressed by finding new and more effective antibiotics.

 Recent studies have shown an increasing incidence of antibiotic resistance in dacryocystitis. Management of diseases may include determining microbial agents and choosing appropriate antibiotics for treatment.

 This study aimed to present the best treatments for dacryocystitis. To this end, specimens' microbiology and antibiotic susceptibility were examined in patients with dacryocystitis in the microbiology laboratory of the Kashan University of Medical Sciences.

 This cross-sectional study was performed on 172 patients presenting with acute and chronic dacryocystitis at the Matini Hospital, Kashan, between 2017 - 2018. Patient characteristics, culture isolates, and antimicrobial susceptibility data were collected. The PCR assay of the mecA gene was performed in all methicillin-resistant Staphylococcus isolates.

 The most common bacteria were coagulase-negative staphylococci (CoNS), Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii. The majority of the isolated microbes were sensitive to rifampicin, linezolid, amikacin, and gentamicin. In Gram-negative bacilli, nine of the isolates were extended-spectrum beta-lactamase positive. The PCR test showed the frequency of mecA gene of resistant S. aureus and resistant CoNS isolates to be 40 and 46.3%, respectively.

 Coagulase-negative staphylococci were the most frequently isolated bacteria. The highest antibiotic susceptibility was observed to rifampin, linezolid, amikacin, and gentamicin. A high percentage of CoNS carried the mecA gene.

 Early-onset neonatal sepsis (ENOS) is one of the most common causes of mortality in neonates. The bacteria causing ENOS are generally transferred from the mother to the infant before or during labor.

 This study aimed to determine the prevalence rate of nasopharyngeal colonization with common bacterial agents causing ENOS and their relationship with blood culture outcomes in neonates.

 All neonates transferred to the neonatal intensive care unit were included in the study. Posterior pharynx secretions were swabbed and cultured in blood agar and MacConkey agar. Also, a blood specimen from each neonate was inoculated into a blood culture bottle. The grown bacteria were identified by biochemical standard tests. The antibiotic sensitivity test was performed by the disk diffusion method using Mueller-Hinton agar, and the results were evaluated according to the CLSI guidelines.

 The pharyngeal specimens collected from 114 newborns were positive in 83 (72.8%) cases. Staphylococcus epidermidis was the most common bacterium in all weight groups. However, the isolates of Klebsiella, Escherichia coli, S. aureus, and Streptococcus agalactiae were also high. Thirteen newborns died. Neonates’ pharyngeal specimens were positive among 11 (84.6%) cases who died and 101 (71.2%) neonates who survived. Twelve neonates had positive blood cultures. Simultaneous positive blood and pharyngeal cultures were reported in eight (7%) cases, in which the bacterial isolates from blood and pharyngeal samples were similar in three cases (37.5%). Among pharyngeal isolates, E. coli was resistant to ampicillin in 100% and gentamicin, cefotaxime, and ceftazidime in 50% of the cases. Also, S. epidermidis and Acinetobacter isolates from blood samples were resistant to ampicillin in 100% of the cases.

 Staphylococcus epidermidis accounted for 38.6% of bacteria cultured from pharyngeal swabs and 66.7% of bacteria cultured from blood samples, 37.5% of which were resistant to ampicillin and 100% were sensitive to vancomycin. One-hundred percent of E. coli cultures from neonatal pharynges were resistant to ampicillin and about 50% of them were resistant to gentamicin, cefotaxime, and ceftriaxone.
 

 Pseudoexfoliation syndrome (PES) is a systemic disease characterized by the aggregation of fibrillar extracellular material in intraocular and extraocular tissues with unknown etiology. Clarifying the etiopathogenesis of PES would be important for public health.

 We aimed to investigate the possible role of Chlamydia in the etiology of PES.

 This cross-sectional study was carried out in the ophthalmology clinic of a tertiary hospital. The study included two groups, including the patient group (PES patients with nuclear cataracts) and the control group (patients with nuclear cataracts). Patients with other ophthalmic problems and systemic diseases were excluded. Blood samples and conjunctival swabs taken from 49 patients and 42 controls were used in the study. Anti-Chlamydia trachomatis IgG and IgM, anti-C. pneumoniae IgG and IgM, Interleukin (IL)-6, and IL-20 were studied in the serum samples. The PCR study was performed with conjunctival swab samples and sequence analysis of PCR-positive samples was performed.

 According to the results of the study, there was no statistically significant difference between the groups in terms of anti-C. trachmatis IgG, anti-C. trachmatis IgM, anti-C. pneumoniae IgM, IL-6, and PCR results. There was a statistically significant difference between patient and control groups in terms of anti-C. pneumoniae IgG and IL-20 levels. The DNA sequencing of all PCR products was found to be compatible with C. pneumoniae.

 It seems that C. pneumoniae might have an important role in the etiology and development of PES. However, further studies in larger groups are needed to clarify these results.

 Human polyomavirus BK virus (BKV) belongs to the Polyomaviridae family and seems to be a drastic virus in prostate cancer (PCa) etiology. BK virus induces oncogenesis via the expression of large tumor antigen (LTAg) and small tumor antigen (stAg). Also, BKV infection seems to play an essential role in prostate cancer development.

 In this study was aimed to study the prevalence of BKV in benign and cancerous prostate tissues.

 In this study, 100 formalin-fixed paraffin-embedded tissues of PCa specimens and benign prostatic hyperplasia (BPH) were collected. The DNA was extracted from tissue samples, and the BKV DNA was investigated using a semi-nested polymerase chain reaction (PCR). The MEGA 6.0 software was used for phylogenetic analysis to assemble the viral genome. A phylogenetic tree was constructed by neighbor-joining analysis with 1,000 replicates of the bootstrap resampling test.

 The BKV DNA was found in 66% (33/50) of patients with PCa and 36% (18/50) of patients with benign prostatic hyperplasia (BPH) (P = 0.003). The frequency of BKV DNA in different classes of Gleason score (5 - 10) was not significant (0.094). The distribution of BKV DNA among different age groups was not significant (P = 0.086).

 High frequency of BKV infection was detected in patients with PCa compared to patients with BPH (P = 0.003), and the coexistence of BKV DNA was confirmed in 51% (51/100) of tissue samples, which were confirmed to be subtype 1 of BKV infection.
 

 Taqman one-step real-time PCR (RT-PCR) has special importance due to its high sensitivity and specificity in the diagnosis of infectious diseases such as viral infections. In the recent pandemic of SARS-CoV-2, diagnostic kits based on this method are commonly used for molecular detection. One of the main systematic errors that misinterpret the results is using inaccurate internal control in RT-PCR diagnostic kits. Designing primers and probes that span exon-exon junction will avoid genomic DNA amplification and lead to obtaining high specific results.

 This study aimed to evaluate the endogenous internal control of primers and probe for RNase P RNA to reduce false-negative results in respiratory samples.

 In this study, 30 samples of patients who were negative for SARS-CoV-2, influenza A, and influenza B were re-evaluated for SARS-CoV-2 using newly designed primers and probes for RNase P RNA (ultra-specific primers and probe). We also performed bioinformatics analysis on CDC-approved primers and probes of RNase P endogenous internal control.

 In this analysis, we specified the location of these newly designed primers and probe on target mRNA and genomic DNA. Then, the Taqman one-step RT-PCR method was performed using both CDC-approved primers and probes along with our ultra-specific primers and probe for RNase P RNA. Based on bioinformatics analysis, the attachment sites of the CDC-approved primers and probe for endogenous internal control of RNase P are located on the first exon of this gene. In addition to identifying the target gene sequence, these primers and probe also non-specifically detect similar sequences on the genomic DNA.

 The present study showed that the use of specific primers and probes introduced by CDC for SARS-CoV-2 and influenza virus may cause false results due to non-specific binding to the genomic DNA. Therefore, choosing the right internal control for RNase P RNA can be useful in achieving very accurate results.