Probiotics: an update on mechanisms of action and clinical applications

Probiotics are live microbial feed supplement and can provide health benefit to the host if administered in sufficient amounts. The most predominant species that have been used as probiotic include Lactobacilli and bifidobacteria. Proper administration of probiotics could be efficient in the treatment of various disorders. However; their mechanism of action is poorly understood. The effects of probiotics may be classified in following modes: reinforcement of the intestinal mucosal barrier against pathogens, competition with pathogens for adherence to the mucosa and epithelium, competitive exclusion of pathogenic microorganisms, production of antimicrobial substances, modulation of the immune system and interference with quorum sensing signaling. Exploration of the clinical features of probiotic strains, their modes of action and investigation based on probiotic therapy may be beneficial in treatment of various diseases

Study of flagellin profiling in multidrug resistant Pseudomonas aeruginosa (MDRPA) isolated from burn wound infections, Tehran, Iran

     Nosocomial infections of multidrug-resistant Pseudomonas aeruginosa (MDRPA) are a growing concern in hospitalized patients in burn centers. The aim of this study was to investigate the flagellin profiling and antibiotic susceptibility of P. aeruginosa isolated from burn wound infections. During 8 month study, 73 clinically P. aeruginosa isolates collected from patients hospitalized in burn ward. P. aeruginosa isolates were identified using standard laboratory procedures. In vitro susceptibility of clinical isolates of P. aeruginosa to 6 antimicrobial agents were investigated by Clinical and Laboratory Standards Institute (CLSI 2012) Kirby-Bauer disk diffusion assay. The frequency of different type of flagellin was investigated by using specific primers and by PCR method. The resistance rates of our isolates to 6 tested antimicrobial agents were relatively high. Imipenem has good activity while tobramycin and ciprofloxacin do not have any effect on P. aeruginosa isolates. Of 73 isolates 59 (80.8%) were multidrug resistant. Twenty eight of 73 isolates were resistant to all antibiotics. Agarose gel electrophoresis of chromosomal DNA exhibited that 59 isolates (80.8%) of P. aeruginosa had type A flagellin while only 14 isolates (19.2%) had type b flagellin. Given the antibiotic failure treatment, it appears that alternative ways such as immunity to prevent of these infections could be informative. Our survey of flagellin profiling of multidrug-resistant P. aeruginosa isolates exhibited high frequency of type a flagellin as a major virulence factor has important role of immunity against infections caused by MDRPA. Functional surveillance of multidrug-resistant P. aeruginosa in order to prevention of resistance dissemination is necessary.

Distribution and Antibiotic Resistance Pattern of Bacteria Isolated from Patients with Community-acquired Urinary Tract Infections in Iran: A Cross-sectional Study

Background: Urinary tract infections (UTIs) remain the common infections diagnosed in outpatients as well as hospitalized patients. Multi-drug resistance (MDR) and extensively-drug resistance (XDR) in bacteria is an alarming problem in the world. The aim of this study was to detection of etiologic agents associated with community-acquired urinary tract infections (CA-UTIs) and investigation of antibiotic susceptibility patterns.Methods: This study was performed from September 2014 to March 2015 on outpatients, which referred to Labbafinejad Hospital Clinic, Tehran, Iran. The bacterial pathogenic diversity identified by standard laboratory methods. The antimicrobial resistance rates were performed by Kirby Bauer disc diffusion methods.Results: A total of 303 patients were enrolled in this study, from which 204 (67.3%) were female and 99 (32.5%) were male patients. Escherichia coli was the dominant species (69%), followed by Enterococcus faecalis (12.8%) and Klebsiella pneumoniae (4.6%). High resistance rate to nalidixic acid (73.8%), trimethoprim/Sulfamethoxazole (54.3%), ciprofloxacin (54.3%) in E. coli,  and tetracycline (89.7%) in E. faecalis strains and high susceptibility rate to meropenem (96.6%), imipenem (95.2%), amikacin (90.4%), cefoxtin (87.6%), and  nitrofurantoin (82.8%)  in E. coli,  and nitrofurantoin (100%)                                                                                                                                                                                                                                                                                                                                                                      in E. faecalis strains were observed. In addition, 43.5% of the strains were multidrug-resistant (MDR).Conclusions: This study showed that E. coli was the predominant uropathogen of CA-UTIs in this geographical area. It also demonstrated the empirical treatment of urinary tract infections may be difficult due to high resistance to commonly used antibiotics. Continuous monitoring of MDR organisms and drug resistance patterns are needed to prevent treatment failure and reduce selective pressure. These findings suggest the use of nitrofurantoin, cefoxitin, and amikacin in this area of the country

Distribution and Antibiotic Resistance Pattern of Bacteria Isolated from Patients with Community-acquired Urinary Tract Infections in Iran: A Cross-sectional Study

Background: Urinary tract infections (UTIs) remain the common infections diagnosed in outpatients as well as hospitalized patients. Multi-drug resistance (MDR) and extensively-drug resistance (XDR) in bacteria is an alarming problem in the world. The aim of this study was to detection of etiologic agents associated with community-acquired urinary tract infections (CA-UTIs) and investigation of antibiotic susceptibility patterns.Methods: This study was performed from September 2014 to March 2015 on outpatients, which referred to Labbafinejad Hospital Clinic, Tehran, Iran. The bacterial pathogenic diversity identified by standard laboratory methods. The antimicrobial resistance rates were performed by Kirby Bauer disc diffusion methods.Results: A total of 303 patients were enrolled in this study, from which 204 (67.3%) were female and 99 (32.5%) were male patients. Escherichia coli was the dominant species (69%), followed by Enterococcus faecalis (12.8%) and Klebsiella pneumoniae (4.6%). High resistance rate to nalidixic acid (73.8%), trimethoprim/Sulfamethoxazole (54.3%), ciprofloxacin (54.3%) in E. coli,  and tetracycline (89.7%) in E. faecalis strains and high susceptibility rate to meropenem (96.6%), imipenem (95.2%), amikacin (90.4%), cefoxtin (87.6%), and  nitrofurantoin (82.8%)  in E. coli,  and nitrofurantoin (100%)                                                                                                                                                                                                                                                                                                                                                                      in E. faecalis strains were observed. In addition, 43.5% of the strains were multidrug-resistant (MDR).Conclusions: This study showed that E. coli was the predominant uropathogen of CA-UTIs in this geographical area. It also demonstrated the empirical treatment of urinary tract infections may be difficult due to high resistance to commonly used antibiotics. Continuous monitoring of MDR organisms and drug resistance patterns are needed to prevent treatment failure and reduce selective pressure. These findings suggest the use of nitrofurantoin, cefoxitin, and amikacin in this area of the country

Fecal carriage of Escherichia coli and Klebsiella spp. as major reservoirs of clinically important resistance markers

Intestinal normal flora can become reservoirs of antibiotic resistance genes present among the strains responsible for nosocomial infections. It is suggested that gram negative intestinal bacterial flora have increased capacities to obtain antibiotic resistance genes and therefore can act as main reservoirs for transfer of resistance genes to other pathogenic bacteria. This study aimed to compare fecal carriage of clinically important resistance markers for more frequent members of enterobacteriacae between nondiarrheal and community associated diarrheal patients (control group) versus their counterparts from the patients with nosocomial infections (case group). 261 stool and 190 clinical samples were collected from outpatient and hospitalized patients from 6 hospitals in Tehran, Iran. The samples were cultured on MacConkey agar plates and colonies were identified by standard biochemical methods. Antibiotic sensitivity testing of the isolates against 13 antibiotics was performed according to the CLSI guideline using the disk diffusion method.   Among stool and clinical samples, more frequent identified enterobacteriaceae bacteria were included E. coli (58.99/ 3.15%), Klebsiella spp. (22.61/7.36%), and other members of enterobacteriaceae (8.86/1.06%), respectively. Overall, resistance against four of the main antibiotics (3th and 4th generation cephalosporins, gentamicin, imipenem, and ciprofloxacin) was significantly higher among the case group (50-75% versus 10-14%). Analysis of these results showed similar dissemination of resistance phenotypes among the isolates from the control group in ranges of 1.5-7.6% and 4.4% for E. coli and Klebsiella spp., respectively. Our results suggested that the fecal carriage of resistant phenotypes related to the β-lactam antibiotics in E. coli and Klebsiella spp. in compare to the clinical isolates is rapidly increasing. This may be caused by dissemination of β-lactamase producing E. coli in the community from the hospitals. There were no significant correlations between the two groups of the samples, as the clinical samples had shown 3 to 7 folds excess resistance phenotypes. Surveillance studies of the resistance patterns among the samples from different regions will provide awareness about dissemination of these bacteria within the community as reservoirs of main resistance markers

First detection of efrAB, an ABC multidrug efflux pump in Enterococcus faecalis in Tehran, Iran

Enterococcus faecalis is one of the most significant pathogen in both nosocomial and community-acquired infections. Reduced susceptibility to antibiotics is in part due to efflux pumps. This study was conducted on 80 isolates of E. faecalis isolated from outpatients with urinary tract infection during a period of 1 year from April 2014 to April 2015. The antibiotic susceptibility patterns of isolates were determined by the disk diffusion method and presence of efrA and efrB genes was detected by PCR and sequencing. Minimum inhibitory concentrations (MICs) to ciprofloxacin (CIP) were measured with and without carbonyl cyanide 3-chlorophenylhydrazone (CCCP) by broth microdilution. The highest resistance rate was observed to erythromycin (83.3%) and the prevalence of efrA and efrB genes in all E. faecalis isolates was 100%. This study showed that 9 out of 13 (69.2%) ciprofloxacin-resistant isolates became less resistant at least fourfolds to CIP in the presence of efflux pump inhibitor. Our result showed that CCCP as an efflux inhibitor can increase effect of CIP as an efficient antibiotic and it is suggested that efrAB efflux pumps are involved in resistance to fluoroquinolone

Capsular Genotypes Distribution and Antibiotic Resistance pattern of Group B Streptococcus (GBS) Isolated from Clinical Samples, Tehran, Iran

Group B Streptococcus (GBS) is an opportunistic harmless bacterium which the leading cause of neonatal infections. Our purpose was to determine capsular genotypes distribution and antibiotic resistance pattern of GBS isolated from clinical samples. Two hundred and twenty two GBS strains isolated from clinical samples from different hospitals in Tehran, Iran. After identification by specific cultures and biochemical tests, broth microdilution method was used to determine the minimal inhibitory concentration (MIC) of antibiotics based on standard protocol. The erythromycin-clindamycin double-disk test was used to determine the inducible resistance phenotypes. Capsular genotypes were identified by PCR method. The high rates of antibiotic resistance in GBS were related to gentamycin 89.18%, tetracycline 87.38%, kanamycin 62.16%, clindamycin (67.1%), erythromycin 57.2%, and chloramphenicol 32.8%. All strains were sensitive to vancomycin, penicillin, and ampicillin. Between eleven capsular antigens, serotypes such as III(50.9%) ,V(27.47%) ,Ib(17.76%) ,Ia(15.54%) , Ic (5.85%)were the highest. The genotypes distribution and the patterns of resistance phenotypes of GBS may vary in different areas. Thus, it is required to be considered in each region to work out strategies for prevention. The PCR method is recommended as a rapid and reliable technique for identification and molecular epidemiology study of GBS

Device-associated infection rates and bacterial resistance in six academic teaching hospitals of Iran: Findings from the International Nocosomial Infection Control Consortium (INICC)

Summary: Device-associated health care-acquired infections (DA-HAIs) pose a threat to patient safety, particularly in the intensive care unit (ICU). However, few data regarding DA-HAI rates and their associated bacterial resistance in ICUs from Iran are available. A DA-HAI surveillance study was conducted in six adult and pediatric ICUs in academic teaching hospitals in Tehran using CDC/NHSN definitions. We collected prospective data regarding device use, DA-HAI rates, and lengths of stay from 2584 patients, 16,796 bed-days from one adult ICU, and bacterial profiles and bacterial resistance from six ICUs. Among the DA-HAIs, there were 5.84 central line-associated bloodstream infections (CLABs) per 1000 central line-days, 7.88 ventilator-associated pneumonias (VAPs) per 1000 mechanical ventilator-days and 8.99 catheter-associated urinary tract infections (CAUTIs) per 1000 urinary catheter-days. The device utilization ratios were 0.44 for central lines, 0.42 for mechanical ventilators and 1.0 for urinary catheters. The device utilization ratios of mechanical ventilators and urinary catheters were higher than those reported in the ICUs of the INICC and the CDC's NHSN reports, but central line use was lower. The DA-HAI rates in this study were higher than the CDC's NHSN report. However, compared with the INICC report, the VAP rate in our study was lower, while the CLAB rate was similar and the CAUTI rate was higher. Nearly 83% of the samples showed a mixed-type infection. The most frequent pathogens were Acinetobacter baumannii, Staphylococcus aureus and Pseudomonas aeruginosa, followed by Klebsiella pneumoniae and Enterococcus spp. In the S. aureus isolates, 100% were resistant to oxacillin. Overall resistances of A. baumannii and K. pneumonia to imipenem were 70.5% and 76.7%, respectively. A multiple drug resistance phenotype was detected in 68.15% of the isolates. The DA-HAI rates in Iran were shown to be higher than the CDC-NHSN rates and similar to the INICC rates. Resistance to oxacillin and imipenem was higher as well. Comparing device use, DA-HAI rates, and bacterial resistance for the primary isolated bacteria indicated a direct association between urinary catheter use and the rates of CAUTI. Keywords: Hospital infection, Iran, INICC, International Nosocomial Infection Consortium, Device-associated infection, Bacterial resistanc