Antibiotic Susceptibility and Biofilm Formation of Bacterial Isolates Derived from Pediatric Patients with Cystic Fibrosis from Tehran, Iran

Cystic fibrosis (CF) is a genetic disease with a high rate of morbidity and mortality. Children with CF commonly suffer from recurrent and persistent pulmonary tract infections caused by diverse bacterial pathogens. This study aimed to investigate the prevalence, antimicrobial susceptibility, and biofilm formation of bacterial isolates in pediatric patients with CF. The study population of this cross-sectional study included 8,908 children suspected to have CF by clinical manifestations from March 2015 to August 2017 who were referred to the Tehran Pediatric Central Hospital, Iran. The tests carried out for each participant included screening sweat test, sputum culture, antibiotic susceptibility test using Kirby-Bauer disk diffusion method, and biofilm formation in microtiter plates method. Based onclinical examination and screening sweat test, 183 (2.05 %( out of 8,908 children, were positive for CF. The mean age of children was estimated at 2.93 years, and the majority of them were male (n=103, 56.2%). No gender-specific difference was observed in CF disease in this study (P>0.05). In addition, the results of sputum culture showed that 153 (83.6%) microorganisms (bacteria and fungi) were collected from CF patients. Normal flora was isolated in 30 (16.4%) patients and more than one bacterial species were isolated in 7.2% of patients. The obtained results indicated that Pseudomonas aeruginosa was the most prevalent isolated bacteria followed by Staphylococcus aureus, and Klebsiella pneumoniae. Based on the antibiotic susceptibility test results, P. aeruginosa and piperacillin/tazobactam had the highest (11.7%) and the lowest (2.3%) resistance rate against gentamicin, respectively. However, all K. pneumoniae isolates were resistant to Cefotaxime. Among S. aureus isolates, 83.4% and 16.6% were methicillin-susceptible Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus respectively. Concerning biofilm formation, 76%, 67%, and 72.5% of P. aeruginosa, S. aureus, and K. pneumoniae isolates were biofilm producers, respectively. Based on the study results, P. aeruginosa was the dominant pathogen in pediatric patients with CF from Tehran, Iran, and most of the pathogens were biofilm producers. No severe antibiotic resistance was observed in the isolates; however, the anti-microbial resistance profile should be carefully checked in CF patients on a regular basis.

Evaluation of IFN-gamma serum level in nephropatic type 2 diabetic patients

The present study was aimed to examine the serum level of IFN-gamma in type 2 diabetic patients with nephropatic complications. In this experimental study, serum samples were obtained from 100 type 2 diabetic patients suffering from nephropathy and 100 healthy controls. Serum level of IFN-gamma was analyzed by ELISA. Results of this study showed that the mean serum level of IFN-gamma was 16.09 +/- 2.04 and 4.03 +/- 1.00 pg mL(-1) in nephropathic patients and healthy controls, respectively. Statistical analysis of data showed that the difference in the IFN-gamma serum level was significant between nephropathic patients and controls. Due to the elevated level of IFN-gamma in nephropathic patients, it can be possibly concluded that IFN-gamma is involved in nephropathy complication of type 2 diabetes.

Apoptosis of ejaculated human sperm is induced by co-incubation with Chlamydia trachomatis lipopolysaccharide

BACKGROUND

Previous work has shown that co-incubation of human sperm with Chlamydia trachomatis serovars E and LGV leads to premature sperm death and that this is due primarily to chlamydial lipopolysaccharide (LPS). Here, we investigated the possible involvement of apoptosis in this premature sperm death.

METHODS

Highly motile preparations of sperm from normozoospermic patients were co-incubated for 6 h with extracted LPS from C. trachomatis serovars E and LGV. Three different methods were used to determine if LPS-treated sperm underwent apoptosis, including: (i) flow cytometry; (ii) measurement of ADP:ATP ratios; and (iii) measurement of mono- and oligonucleosomal DNA fragments. Caspase activity was also investigated by fluorimetry and by use of a pan-caspase inhibitor and caspase-3 inhibitor.

RESULTS

All three methods used for detection indicated that C. trachomatis LPS induced some apoptosis in sperm after 6 h when compared with a staurosporine (apoptosis-positive) control. Moreover, a greater degree of apoptosis was seen with C. trachomatis serovar E than with serovar LGV. It was also shown that C. trachomatis LPS-induced apoptosis of sperm could be blocked with a pan-caspase inhibitor and a caspase-3 inhibitor. Moreover, by using a fluorogenic substrate, apoptosis was shown to be caspase-mediated.

CONCLUSIONS

In general it is believed that apoptosis does not occur in C. trachomatis-infected host cells. However, using three different methods, our findings clearly indicate that co-incubation of sperm with C. trachomatis LPS results in cellular death which is in part due to apoptosis and is caspase-mediated. These findings provide an explanation as to how C. trachomatis can mediate premature death in human sperm.