Background: β-Lactam antibiotics have been broadly used for the treatment of Acinetobacter baumannii infections, resulting in development of β-lactam inactivating β-lactamases. Here, we described antibiotic resistance rate, prevalence of β-lactamase-encoding genes, and clonal relationships of A. baumannii strains isolated from children referred to Children’s Medical Center in Tehran, Iran, during 2019–2020. Methods: A total of 60 non-replicate A. baumannii isolates were recovered from clinical specimens of pediatric patients. Antibiotic susceptibility testing was done by the disc diffusion method. Colistin susceptibility of isolates was performed by the broth microdilution method. β-lactamase-encoding genes were characterized by PCR. The presence of ISAba1 element upstream of the several oxacillinase genes was also checked. Genetic relatedness of isolates was determined by using random amplification of polymorphic DNA (RAPD) typing. Results: The antimicrobial susceptibility tests showed that 83.3% of A. baumannii isolates were MDR, and 40% XDR. Both MDR and XDR A. baumannii isolates were susceptible to colistin. The frequency of bla_OXA-51-like, bla_OXA-23-like, bla_TEM, bla_OXA-24-like, bla_PER, bla_SHV, bla_CTX-M, bla_OXA-58-like, and bla_IMP was 100, 93.33, 60, 36.67, 28.33, 8.33, 5, 3.33, and 1.67%, respectively. Coexistence of ISAba1/bla_OXA-23-like and ISAba1/bla_OXA-51-like was observed in 65% and 85% of isolates, respectively. RAPD analysis revealed 4 common types and 2 single types of A. baumannii isolates. Conclusions: The multiple clones harboring bla_OXA-23-like, ISAba1-bla_OXA-51-like, and ISAba1-bla_OXA-23-like were responsible for the spread of A. baumannii isolates in our clinical wards. Dissemination of the well-established clones is worrisome and would become therapeutic challenges due to the possible transferring genetic elements associated with resistance.

Azithromycin (AZT) has widely been used for the treatment of shigellosis in children. Recent studies showed a high rate of decreased susceptibility to azithromycin due to different mechanisms of resistance in Shigella isolates. Accordingly, the purpose of this study was to investigate the role of azithromycin resistance mechanisms of Shigella isolates in Iran during a two-year period. In this study, we investigated the mechanisms of resistance among Shigella spp. that were isolated from children with shigellosis. The minimum inhibitory concentration (MIC) of Shigella isolates to azithromycin was determined by the agar dilution method in the presence and absence of Phe-Arg-β-naphthylamide inhibitor. The presence of 12 macrolide resistance genes was investigated for all isolates by PCR for the first time in Tehran province in Iran. Among the 120 Shigella spp., only the mph(A) gene (49.2) was detected and other macrolide resistance genes were absent. The phenotypic activity of efflux pump was observed in 1.9 of isolates which were associated with over expression of both omp(A) and omp(W) genes. The high prevalence of the mph(A) gene among DSA isolates may indicate that azithromycin resistance has evolved as a result of antimicrobial selection pressures and inappropriate use of azithromycin.

Background: Hospital-acquired infections (HAIs), specifically those caused by gram-negative bacteria, are a significant public health concern with high mortality rates among patients worldwide, especially in developing countries. Objectives: This survey aimed to determine the prevalence and antibiotic resistance patterns of gram-negative nosocomial infections among patients admitted to different wards of a tertiary hospital in Iran. Methods: This cross-sectional study was conducted using samples collected from patients admitted to coronary care unit (CCU), intensive care unit (ICU), neonatal intensive care unit (NICU), general, and surgery wards of Yas Hospital, Tehran, Iran, from October 1st, 2022, to February 28th, 2023. After the detection of bacteria, antibiotic susceptibility tests were performed using the Kirby-Bauer disk diffusion method by the guidelines of the clinical and laboratory standards institute (CLSI) for gentamycin (GM), ciprofloxacin (CIP), cefepime (FEP), ceftazidime (CAZ), cefotaxime (CTX), imipenem (IPM), meropenem (MR), and piperacillin-tazobactam (TZP), and the results were analyzed using SPSS v22 software. Results: Two hundred and sixty isolates were collected from clinical specimens, most of which were isolated from the ICU ward (53.8%). Among the collected specimens, 98 (37.7%) were isolated from urine, 92 (35.4%) from sputum, 45 (17.3%) from blood, 17 (6.5%) from surgical wounds, and 8 (3.1%) belonged to other specimen types. Among detected bacteria, Klebsiella pneumoniae and Escherichia coli were found to be responsible for 78% of total infections. Based on the Kirby-Bauer disk diffusion results, Acinetobacter baumannii demonstrated the highest resistance to the antibiotics tested, with a resistance rate ranging from 92% to 97%. This was followed by K. pneumoniae, which demonstrated resistance rates between 70% and 85% across all classes of tested antibiotics. Conclusions: The study highlights a high prevalence of nosocomial infections in the ICU, with significant antibiotic resistance, particularly from A. baumannii. It emphasizes strict hospital monitoring, infection control, and responsible antibiotic use.

Background. In this study, attempts were made to evaluate the frequency of high‐level gentamicin‐resistant (HLGR) and vancomycin‐resistant enterococci (VRE) and the prevalence and antibiotic resistance profile of enterococcal species isolated from pediatric patients referred to Children’s Medical Center Hospital, Tehran, over five years. Materials and Methods. A total of 404 enterococcal isolates from different patients referred to the Children’s Medical Center between March 2016 and March 2021 were included in this cross‐sectional study. Antimicrobial susceptibility testing was performed using standard methods according to the guidelines of the Clinical Laboratories Standards Institute (CLSI). Results. Approximately one‐third of the enterococcal strains were isolated from urology and intensive care units. 17.3% of the isolates were obtained from outpatient sources. However, 82.7% of the isolates were sourced from inpatient settings. We found that the rates of resistance to ampicillin, penicillin, and vancomycin were twice as high in inpatients as in outpatients. Of the total isolates, 87.4% and 49.3% were identified as HLGR and VRE, respectively. In addition, we identified 2% of the VRE isolates that were not susceptible to linezolid. Nitrofurantoin showed excellent activity against enterococcal isolates in the urine, with a susceptibility rate of 92.5%. Conclusion. The present study reports the highest range of VRE isolated from pediatric patients in Iran. Despite the predominance of HLGR enterococci in our region, vancomycin remains effective against such strains. This study is among the few to demonstrate the incidence of linezolid‐insensitive VRE in pediatric patients. Therefore, it is important to evaluate effective infection control measures to prevent linezolid and vancomycin resistance in enterococci.

Introduction: Despite substantial advances in infection control for infants, neonatal sepsis remains a major cause of morbidity and mortality, particularly in pediatric intensive care units (PICUs). Case Presentation: A 49-day-old female infant was admitted to Hakim Hospital with respiratory symptoms. Clinical signs suggestive of pertussis prompted the initiation of empirical antibiotic therapy. Blood cultures subsequently grew Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa), both of which were susceptible to most tested antibiotics, including carbapenems and aminoglycosides. Despite appropriate antibiotic treatment, the patient’s condition deteriorated, and she died 9 days after admission. Conclusions: This case highlights that, in neonatal sepsis, favorable in vitro antibiotic susceptibility does not necessarily predict a successful clinical outcome. Additional host-, pathogen-, and treatment-related factors should be considered when evaluating treatment failure and mortality in critically ill infants.