Screening of healthcare workers for latent tuberculosis infection in the low tuberculosis burden country: QuantiFERON-TB gold in tube test or tuberculin skin test?

Healthcare workers (HCWs) are an important group at increased risk for exposure to various infectious agents including Mycobacterium tuberculosis. Unfortunately, there is very limited data on the prevalence of latent tuberculosis infection (LTBI) among HCWs in Iran. The aim of this study was to analyze the prevalence of LTBI among HCW's of Children Medical Center (CMC), an Iranian referral hospital, and to compare the feasibility of using tuberculin skin test (TST) and QuantiFERON-TB gold in tube test (QFT-GIT) to screen the LTBI among this population. Informed consent was obtained before the study questionnaire was completed. Participants were then evaluated for LTBI using QFT-GIT test followed immediately by TST. The prevalence of latent TB infection in the 101 HCWs, based on QFT-GIT positivity, was 47% (n = 47), while based on TST test a higher prevalence was observed (n = 57, 57%). Forty-five (45%) subjects were positive for both tests, whereas 14 (14%) were positive by either test. Among the TST positive cases, 21% (n = 12) were negative for QFT-GIT. The overall agreement of TST and QFT-GIT was 86% ([45 + 42]/101] and a moderate correlation between these two tests was observed (Kappa value 0.72). The use of QFT-GIT test as a second step in TST-positive cases offers an appropriate tool for LTBI detection in our country where all HCWs are BCG-vaccinated. To enable the effective control and prevention of TB in healthcare settings in Iran, specific and detailed guidelines for dealing with LTBI are highly required. All newly hired HCWs should receive baseline testing for LTBI before commencing employment. In addition, HCWs who work in high-risk departments should receive regular follow-up screening for LTBI.

Antimicrobial resistance patterns of Gram-negative bacteria isolated from bloodstream infections in an Iranian referral paediatric hospital: A 5.5-year study.

OBJECTIVES: Bloodstream infections (BSIs) are a major cause of paediatric morbidity and mortality worldwide. This study describes the epidemiology and antimicrobial resistance of Gram-negative bacteria (GNB) from BSIs in children admitted to an Iranian paediatric hospital. METHODS: Clinical and microbiological data of patients with positive blood cultures were collected from March 2011 to September 2016. Standard laboratory methods were used for blood culture and bacterial identification. Antimicrobial sensitivity was evaluated by the Kirby-Bauer disk diffusion and broth microdilution methods. RESULTS: Of 2325 bacterial pathogens isolated from blood cultures, 41.1% (n=956) were GNB. Most clinical isolates (n=208; 21.8%) were identified in the cardiac intensive care unit. Predominant bacterial isolates were Klebsiella pneumoniae subsp. pneumoniae (n=263; 27.5%), Escherichia coli (n=192; 20.1%), Serratia marcescens (n=151; 15.8%), Pseudomonas aeruginosa (n=111; 11.6%) and Enterobacter spp. (n=100; 10.5%). Enterobacter isolates showed a high level of ampicillin resistance. Escherichia coli were highly resistant to chloramphenicol (100%), cefixime (100%), ceftriaxone (100%) and ampicillin (96%). Cefixime had the least efficacy against Haemophilus spp. (100% resistant). All K. pneumoniae (100%) were ampicillin-resistant. All S. marcescens were ceftazidime-resistant. No Acinetobacter baumannii were resistant to colistin. All P. aeruginosa were resistant to cefotaxime and trimethoprim/sulfamethoxazole. CONCLUSIONS: These results demonstrate the increasing trend in antibiotic resistance among GNB associated with BSI in children, emphasising the importance of continuous screening and surveillance programmes for detection of antibiotic resistance in BSI pathogens for selection of appropriate treatment regimens.

Antibiotic susceptibility of Helicobacter pylori strains isolated from Iranian children: High frequency of A2143G point mutation associated with clarithromycin resistance.

OBJECTIVE: Increasing antibiotic resistance in Helicobacter pylori is a global concern and is associated with treatment failure. The aim of this study was to evaluate antibiotic resistance of H. pylori to different antibiotics including amoxicillin, erythromycin, ciprofloxacin, furazolidone, tetracycline, metronidazole and clarithromycin. In addition, ​detection of A2143G mutation in clarithromycin resistant isolates was performed using real-time PCR technique. METHODS: Ninety patients with upper gastrointestinal symptoms were enrolled in this study. H. pylori were isolated from 32 specimens and the resistance rate of these strains to amoxicillin, erythromycin, ciprofloxacin, furazolidone, and tetracycline was tested by disc agar diffusion method. The resistance level to metronidazole and clarithromycin was determined by agar dilution method. The presence of A2143G point mutation in clarithromycin resistant isolates was determined using real-time PCR technique. RESULTS: The resistance rates to amoxicillin, erythromycin, ciprofloxacin, furazolidone, tetracycline, metronidazole and clarithromycin were 53%, 50%, 37.5%, 62.5%, 25%, 62.5% and 22%, respectively. The A2143G point mutation was detected in 71% of clarithromycin resistant strains (5 out of 7). CONCLUSIONS: The prevalence of H. pylori resistance to metronidazole, ciprofloxacin, erythromycin, amoxicillin and furazolidone in Iran is high. Determination of antibiotic susceptibility plays an important role in selecting of the appropriate anti H. pylori regimen.

Prevalence and antimicrobial susceptibility of Salmonella and Shigella spp. among children with gastroenteritis in an Iranian referral hospital.

BACKGROUND: Gastroenteritis is one of the leading cause of illnesses through the world, especially in developing countries.Salmonella and Shigella infections are considered as the main public health problems in children. The aim of this study was to detect the prevalence and antimicrobial susceptibility of Salmonella and Shigella spp. among children with gastroenteritis in an Iranian referral hospital. METHODS: During April 2013 to April 2014, all medical records of children with gastroenteritis admitted to a pediatric medical center were evaluated. Positive stool cultures of children were evaluated and frequency of Salmonella and Shigella spp. and their antimicrobial susceptibility were detected. RESULTS: In this study, 676 patients with the mean age of 24.94 months were enrolled. Eighty-eight (42%) Salmonella spp., 85 (40%) Shigella spp., 33 (16%) E. coli and 5(2%) candida albicans were isolated from 211 positive stool cultures. Among 85 Shigella spp. isolates, S. sonnei, S. flexneri and other Shigella spp. were isolated from 39 (46%) isolates, 36(42%) and 10(12%), respectively. Among 88 isolated Salmonella spp., 36 (41%) isolates were Salmonella Serogroup D, 26 (30%) were Salmonella Serogroup B, 20 (23%) isolates were Salmonella Serogroup C and 6 (7%) were other Salmonella spp. isolates. Thirty-eight percent of Salmonella serogroup B were resistant to nalidixic acid, while higher frequency of nalidixic acid resistant was found in Salmonella serogroup C and Salmonella serogroup D. The higher frequency of ampicillin resistant was found in Shigella spp. than Salmonella spp. High frequency of cefotaxime resistant was seen in S. sonei and S. flexneri (77% and 56%, respectively), whereas more than 90% of Salmonella serogroup B, C and D were susceptible to this antibiotic. CONCLUSION: In conclusion, Shigella and Salmonella serogroups can be considered as important etiological agents of acute diarrhea in children. Since the prevalence of antibiotic resistance is increasing in recent years in Iran, further studies on the prevalence, antimicrobial susceptibility pattern and mechanisms of antibiotic resistance in these species is highly recommended.

Molecular epidemiology of Staphylococcus aureus nasal colonization among patients and their parents /guardian in an Iranian referral hospital.

INTRODUCTION: Carriage of Staphylococcus aureus in the nose appears to play a key role in the epidemiology and pathogenesis of infection. It is important to investigate the genetic relatedness of S. aureus and MRSA clones in different geographic regions. The aim of this study was to assess the nasal carriage rate of S. aureus, including MRSA strains in both hospitalized children and general adult population (parents/guardian). In addition, antibiotic susceptibility pattern and molecular diversity of S. aureus in both population was evaluated in an Iranian referral pediatrics Hospital. MATERIAL AND METHODS: All samples were obtained through nasal screening of patients and general adult population at admission and discharge day. The prevalence, resistance, and molecular diversity of all S. aureus isolates were examined. RESULTS: In the current study, nasal carriage of S. aureus and Staphylococcus non aureus was identified in 384 (26%) and 1004 (68%) of the study population. The prevalence of MRSA nasal carriage in children and adults was 6.6% (29 out of 438) and 2.8% (29 out of 1046), respectively. Among S. aureus strains isolated obtained from patients and general adult population at admission day, high sensitivity to most of the antibiotics such as vancomycin (100%), rifampin (95%), linezolid (94%), quinupristin/dalfopristin (94%), minocycline (94%), chloramphenicol (89%), gentamycin (87%), amikacin (87%), clindamycin (86%) and moxifloxacin (83%) was seen. The most resistance antibiotics were penicillin (96-98%) and methicillin (44-47%). The susceptibility patterns of nasal S. aureus strains isolated at discharge day was not statistically different from S. aureus isolates obtained at admission day. Admission S. aureus isolated strains of 77 patients (64%) were similar to the isolated S. aureus strains of discharge, while S. aureus isolated strains of 43 patients (36%) was not similar to the strain of discharge (had similarity of less than 70%). CONCLUSION: High prevalence of nasal carriage of S. aureus and MRSA indicates the urgent need to improve strategies for management of S. aureus infections. Our findings are useful for understanding of S. aureus nasal colonization dynamics within the patients and general population. Surveillance for S. aureus in community settings can provide data on circulating strains and might help developing control measures for reducing of infection spread in hospitals.

Clinical, cytological and microbiological evaluation of bronchoalveolar lavage in children: A referral hospital-based study.

INTRODUCTION: Diffuse lung diseases (DLD) in children involve a group of heterogeneous, rare disorders. In spite of the low diagnostic yield in pediatric DLD, bronchoalveolar lavage (BAL) can be used to diagnose specific disorders. There are few studies about microbial and cellular profiles of BAL samples in these patients. This study was conducted to evaluate the clinical, cytological and microbiological evaluation of BAL in children with DLD. METHODS: The clinical, cytological and microbiological profiles of BAL samples of all patients with DLD who underwent the fiberoptic bronchoscopy (FOB) at Children's Medical Center, an Iranian referral pediatrics Hospital during a year were evaluated. RESULTS: In 18 patients (18.4%) of the 98 cases studied, 22 pathogens were obtained as etiologic agents. The mean total cells count of BAL was 23.9 × 104 ± 12.9 × 104/ml. The mean percentages of cellular components were macrophages (70.2%), neutrophils (16.3%), lymphocytes (11.8%) and eosinophils (1.4%), respectively. The type of lung disease was significantly associated with the mean percentage of lymphocytes (p = 0.005) and the percentage of neutrophils (p = 0.042). CONCLUSION: FOB and BAL evaluation in combination with clinical and radiographic imaging data may be helpful for identifying of presumptive diagnosis of DLD in children.

Evaluation of efflux pumps gene expression in resistant Pseudomonas aeruginosa isolates in an Iranian referral hospital.

BACKGROUND AND OBJECTIVES: Pseudomonas aeruginosa (PA) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. Among all the resistance-nodulation-division (RND) pumps of P. aeruginosa, MexAB-OprM is the first efflux pump found to target multiple classes of antibiotics. This study was aimed to evaluate the expression level of genes expressing MexAB-OprM in clinical isolates of P. aeruginosa. MATERIALS AND METHODS: In this study, 45 P. aeruginosa strains were isolated from patients admitted to Children's Medical Center Hospital, an Iranian referral hospital. Disk diffusion and Minimum Inhibitory Concentration (MIC) methods were used for determination of the patterns of resistance to antibiotics. Real-time PCR was used to investigate the expression level of genes of MexAB-OprM efflux pump. RESULTS: Among 45 resistant PA isolates, the frequency of genes overexpression was as follows: MexA (n=25, 55.5%), MexB (n=24, 53.3%) and OprM (n=16, 35.5%). In addition, in 28 strains (62%) overexpression was observed in one of the studied three genes of MexAB-OprM efflux pump. CONCLUSION: In our study 28 isolates (62%) had increased expression level of efflux pumps genes, MexAB-OprM. Although the efflux pumps play important roles in increasing the resistance towards different antibiotics but the role of other agents and mechanisms in evolution of resistance should not be ignored. Since the concomitant overproduction of other Mex efflux systems might have additive effects on antibiotic resistance, the co-expressing of a multicomponent efflux pump is recommended. On the other hand, the concomitant overproduction of two Mex pumps might have additive effects on resistance to antibiotic. Therefore co-expressing of Mex efflux systems is recommended.

Adverse reactions to Mycobacterium bovis bacille Calmette-Guérin vaccination against tuberculosis in Iranian children.

PURPOSE: There are considerable variations in the number of adverse reaction reports related to vaccine from different countries. The aim of this study was to review the development of adverse reactions to bacille Calmette-Guérin (BCG) vaccination among hospitalized patients in an Iranian referral hospital. MATERIALS AND METHODS: We identified hospitalized patients with BCG complications in Pediatric Infectious Disease Research Center, Tehran University of Medical Sciences, Tehran, Iran during January 2007-April 2009. Data on demographics, clinical features, laboratory findings, personal history (including vaccination history), family history, and outcomes were retrieved from medical records. RESULTS: There were 46 cases with BCG complication during the 2 years period. All of the children received vaccination at birth. Twenty-eight patients (61%) were male. The mean age of the patients was 13.5 ±11.3 months (range, 1 to 52 months; median, 10 months). The majority of children (57%) with BCG complication were less than 1 year old. Among hospitalized patients due to BCG complications, suppurative lymphadenitis was occurred in 28 children (61%) and lymphadenopathy was seen in 9 children (20%). Disseminated BCG was detected in 8 patients (17%) and only 1 child (2%) was presented with abscess. In 7% (n = 3) of children, the family history of BCG complications were positive. CONCLUSION: The most common side effect of the BCG vaccine in our study was suppurative lymphadenitis. Disseminated BCG infection in complications leading to hospitalization in our study was 17%. With regard to the difficulty in implementing such a guideline in settings where BCG is given to all newborns, registration of Iranian primary immunodeficiency disorders (PID) patients would be helpful to increase the awareness of medical community of Iran to investigate underlying disease. In addition, BCG vaccination should postpone in each newborn with a family history of PID until the definite condition has been ruled out.