Molecular investigation of extended-spectrum β-lactamases (ESBLs) genes in the Salmonella isolates obtained from children with acute diarrhea

Salmonellosis is an important public health concern among children in worldwide. Extended-spectrum β-lactams (ESBLs) cause resistance to clinically important beta-lactams which are generally used to treat invasive Salmonella infections. Therefore, the aim of this study was to investigate the presence of SHV, TEM and CTX-M genes in different strains of Salmonella isolated from children with acute diarrhea and to determine their resistance profile. In this cross-sectional study, 300 fecal samples were collected from children referred to the Amirkola Children's Hospital, Babol, Iran. Antibiotic susceptibility testing was done according to the CLSI guideline. ESBLs-producing strains were identified using double disk synergy test method on the Mueller-Hinton agar plates. Multiplex-PCR was performed using oligonucleotide specific primers to detect of SHV, TEM and CTX-M genes. In total, 7% (n; 21/300) salmonella were isolated, which 61.9%, 28.6% and 9.5% were Salmonella typhimurium, Salmonella enteritidis and Salmonella typhi, respectively. The prevalence of the ESBL-producing isolates were 52.4%. M-PCR results showed that 42.8%, 38.1% and 14.3% of isolates were carried CTX-M, TEM and SHV genes, respectively. Also, 18.2% of isolates harbored CTX-M, and TEM genes, simultaneously. The high rate of ESBLs-producing Salmonella strains in the pediatric patients is an alarm. It is also recommended that alternative drugs be used with less resistance, which requires further investigation

Serological Diagnosis of Helicobacter pylori Infection in Patients With a Polycystic Ovary Syndrome

Background: Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in 4%-6% of women in the reproductive age and is a common cause of infertility. Even though the number of investigations is scarce, studies show that Helicobacter pylori infection may influence reproduction. Objectives: The purpose of this study was to determine and compare the levels of H. pylori specific antibodies IgA, IgG and anti-CagA at both PCOS and non-PCOS women with their spouses using the serological test. Patients and Methods: In this cross-sectional study, 127 women with their spouses (age range, 30 - 60 years) were selected. These patient were referred to infertility center of Shariati Hospital in Tehran, Iran, with a diagnostic criteria of PCOS based on Androgen Excess Society (AES). The specific antibodies of IgA, IgG and anti-CagA were measured using the commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. Results: The positive titers of H. pylori antibodies IgA, IgG and anti-CagA in the PCOS group were 45 (35%), 79 (62%) and 77 (60.5%), respectively, while in non-PCOS group were 38 (30%), 76 (60%) and 50 (39.5%), respectively. The sera positive for IgA, IgG and anti-CagA antibodies in spouses of the non-PCOS group were 38 (30%), 84 (66%) and 79 (62%) respectively, but in spouses of the PCOS group were 51 (40%), 83 (66%) and 48 (38%), respectively. The results showed that H. pylori infection probably did not affect infertility or reproduction. Conclusions: Findings of this study demonstrate no significant difference between levels of H. pylori specific antibodies of IgA, IgG, anti-CagA and the presence of PCOS disorders, and also indicate that serologic testing is a sensitive method for the detection of H. pylori antibodies. The high prevalence of H. pylori positive antibody levels in both PCOS and non-PCOS patients can be probably associated with the high frequency of H. pylori infection

Bacterial Agents and Antibiotic Resistance Profile in Pyelonephritis; A Comparison between Children with and without Urinary Tract Abnormalities in the North of Iran

Background:      Pyelonephritis in children is a serious condition that is commonly encountered in clinical practice. Urinary tract abnormalities increase the risk of urinary tract infections (UTIs) and consequently antibiotic resistance. Our study aimed to evaluate the local trend in terms of bacterial uropathogen resistance in Babol, Iran, in children with pyelonephritis considering urinary tract abnormalities. Methods:      We recruited pediatric cases aged 1 month to 18 years who were admitted to Amirkola hospital with a diagnosis of pyelonephritis from 2016 to 2019. Children with negative urine cultures or incomplete imaging were excluded from the study. Causative agents were identified based on biochemical features. Antimicrobial in vitro resistance tests were performed using the disk diffusion agar test. Results:      A total of 105 children were included in the study. E. coli was the most common causative agent found in 93 (88.6%) patients. Most of the bacterial isolates were sensitive to amikacin and imipenem, and only 12.4% and 13.3% of isolates were resistant to this antibiotic. On the other hand, nalidixic acid represented the least effective treatment, with a resistance rate of 88.6%. A statistically significant difference was observed in resistance to nitrofurantoin and nalidixic acid between children with and without anomalies (p < 0.05). Conclusion:      High antibiotic resistance, especially in children with urinary tract anomalies, was identified for frequently used antibiotics. Our findings provide important implications regarding local patterns of uropathogens and antibiotic resistance in children with pyelonephritis

Tetracycline resistance mediated by tet efflux pumps in clinical isolates of Acinetobacter baumannii

Acinetobacter baumannii is one of the most frequent nosocomial pathogen capable of acquiring resistance to different antimicrobials. The aim of this study was to investigate the activity of tetracycline, doxycycline and minocycline, the prevalence of tet(A) and tet(B) determinants, and the role of efflux pump in tetracycline resistance among the A. baumannii clinical isolates. Susceptibility of 98 A. baumannii isolates to tetracyclines was evaluated by disk diffusion method. The presence of active efflux pump was investigated by determination of the minimum inhibitory concentration (MIC) of tetracycline using the carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Polymerase chain reaction (PCR) was performed to investigate the presence of tet(A) and tet(B) determinants in tetracycline-resistant isolates. The rate of resistance to tetracycline, doxycycline and minocycline was 47.95%, 0%, and 30.61%, respectively. Among the 47 tetracycline-resistant isolates, 29.79% were originated from burned patients and showed MIC ranging from 128-256 µg/mL with both MIC50 and MIC90 values of 256 µg/mL, while 70.21% were from ventilator-associated pneumonia (VAP) patients and had MIC values ranging from 32-1024 µg/mL, with MIC50 and MIC90 of 512 µg/mL and 1024 µg/mL, respectively. The tet(B) gene was found in 61.7% of tetracycline-resistant isolates, while none of the isolates carried the tet(A) gene. CCCP led to 2-128-fold reduction in tetracycline MIC of the tested isolates. The results showed that doxycycline and minocycline are promising agents for the treatment of A. baumannii infections. This study has also revealed the role of efflux activity in the resistance to tetracycline of A. baumannii isolates. The emergence of resistance to these agents is likely due to the spread of clones presenting with a higher prevalence of resistance determinants

Outer Ear Infections in Iran: A Review

BACKGROUND: Otitis externa is the fungal and bacterial infection of the outer ear. AIM: We aimed to investigate the published papers about the outer ear infections in Iran and suggest standardised investigations and treatments. METHODS: We used different electronic databases like PubMed, Scopus, Web of Science, Iranmedex, Google Scholar, and Magiran with specific keywords. RESULTS: We obtained forty published full-text articles for review of data. Our results indicated the women were more infected than men. The ages of patients were &lt; 1-81 years. As clinically symptoms, itching and Feel the ear fairy were the most common presenting complaints in most cases. Most infections were the pure bacterial and fungal origin, respectively. However, some of the studies were mixed fungal-bacterial infections — Pseudomonas spp. And Aspergillus niger were the most common bacteria and fungi isolates respectively in Iranian patents. CONCLUSION: Fungal and bacterial specific cultures may be recommended, and anti-fungal drugs may be added, to treatment regimens in patients with otitis externa to reduce the clinical symptoms

Characterization of Phenotypic and Genotypic Diversity of Stenotrophomonas maltophilia Strains Isolated From Selected Hospitals in Iran

Stenotrophomonas maltophilia is an environmental Gram-negative bacterium that has rapidly emerged as an important nosocomial pathogen in hospitalized patients. Treatment of S. maltophilia infections is difficult due to increasing resistance to multiple antibacterial agents. The purpose of this study was to determine the phenotypic and genotypic characterization of S. maltophilia isolates recovered from patients referred to several hospitals. A total of 164 clinical isolates of S. maltophilia were collected from hospitals in various regions in Iran between 2016 and 2017. Antibiotic susceptibility testing was performed by disc diffusion method and E-test assay according to the Clinical and Laboratory Standards Institute (CLSI) guideline. The ability of biofilm formation was assessed with crystal violet staining and then, biofilm-associated genes were investigated by PCR-sequencing method. The presence of L1 (a metallo-β-lactamase), L2 (a clavulanic acid-sensitive cephalosporinase), sul1 and sul2 (resistance to Trimethoprim/Sulfamethoxazole), Smqnr (intrinsic resistance to quinolones), and dfrA genes (dihydrofolate reductase enzyme that contributes to trimethoprim resistance) was also examined by PCR-sequencing. Relative gene expression of smeDEF efflux pump was assessed by real-time PCR. Genotyping was performed using the multi-locus sequencing typing (MLST) and repetitive extragenic palindromic-PCR (Rep-PCR). Isolates were resistant to imipenem (100%), meropenem (96%), doripenem (96%), and ceftazidime (36.58%). Notably, 5 (3.04%) isolates showed resistant to trimethoprim-sulfamethoxazole (TMP-SMX), an alarming trend of decreased susceptibility to TMP-SMX in Iran. Minocycline and levofloxacin exhibited the highest susceptibility of 91.46 and 99.39%, respectively. Using the crystal violet staining, 157 (95.73%) isolates had biofilm phenotype: 49 (29.87%), 63 (38.41%), and 45 (27.43%) isolates were categorized as strong-, moderate- and weak-biofilm producer while 7 isolates (4.26%) were identified a non-biofilm producer. Biofilm genes had an overall prevalence of 145 (88.41%), 137 (83.53%), and 164 (100%) of rmlA, rpfF, and spgM, respectively. L1, L2, Smqnr, sul1, and sul2 resistance genes were detected in 145 (88.41%), 156 (96.12%), 103 (62.80%), 89 (54.26%), and 92 (56.09%) isolates, respectively. None of the S. maltophilia isolates were positive for dfrA12, dfrA17, and dfrA27 genes. Gene expression analysis showed that smeD efflux system was overexpressed in two out of the five clinical isolates (40%) that showed resistance to TMP-SMX. Most of the isolates were genetically unrelated. Two new sequence types (ST139 and ST259) were determined. Our results showed that TMP-SMX was still an effective antibiotic against S. maltophilia. The findings of the current study revealed an increasing prevalence of antibiotic resistance and biofilm genes in clinical S. maltophilia isolates in Iran

Metallo-β-lactamase-mediated resistance among clinical carbapenem-resistant Pseudomonas aeruginosa isolates in northern Iran: A potential threat to clinical therapeutics

Objective: Carbapenems are effective agents to treat multidrug-resistant (MDR) strains of bacteria, including Pseudomonas aeruginosa. However, there is a potential threat of emergence of carbapenem-resistant P. aeruginosa (CRPA). The aim of this study was to determine antibiotic susceptibility patterns and metallo-beta-lactamase (MBL)-mediated resistance in clinical P. aeruginosa isolates. Materials and Methods: Different clinical specimens were subjected to conventional culture-based identification of P. aeruginosa. Antimicrobial susceptibility patterns and MBL production were evaluated using the Kirby-Bauer and combined double-disk synergy test methods, respectively. Multiplex polymerase chain reaction was performed to investigate the presence of the blaIMP, blaVIM, blaNDM, blaSPM, and blaSIMgenes. Results: A total of 71 clinical P. aeruginosa isolates were recovered, of which 28.17% were identified as CRPA. The most active antibiotics were colistin and polymyxin B (92.96% susceptibility to each). A total of 35% and 50% of CRPA isolates were MDR and extensively drug-resistant (XDR), respectively. MBL activity was shown in 20% of CRPA. A total of 90%, 40%, and 5% of CRPA isolates harbored the blaIMP, blaVIM, and blaNDMgenes, respectively. No correlation was found between the MBL-encoding genes of P. aeruginosa and patient characteristics. Conclusion: Although the prevalence of CRPA in our therapeutic centers was relatively low, this rate of carbapenem resistance reflects a threat limiting treatment choices. A high prevalence of MDR/XDR phenotypes among the MBL-producer isolates suggests the need for continuous assessment of antimicrobial susceptibility and surveillance of antibiotic prescription. In addition, infection control measures are needed to prevent further dissemination of these organisms

PCR-based identification of methicillin–resistant Staphylococcus aureus strains and their antibiotic resistance profiles

Objective: To evaluated the PCR for mecA gene compared with the conventional oxacillin disk diffusion method for methicillin-resistant Staphylococcus aureus (S. aureus) identification. Methods: A total of 292 S. aureus strains were isolated from various clinical specimens obtained from hospitalized patients. Susceptibility test to several antimicrobial agents was performed by disk diffusion agar according to Clinical and Laboratory Standards Institute guidelines. The PCR amplification of the mecA gene was carried out in all the clinical isolates. Results: Among antibiotics used in our study, penicillin showed the least anti-staphylococcal activity and vancomycin was the most effective. The rate of methicillin-resistant S. aureus prevalence determined by oxacillin disk diffusion method was 47.6%; whereas, 45.1% of S. aureus isolates were mecA-positive in the PCR assay. Conclusions: This study is suggestive that the PCR for detection of mecA gene is a fast, accurate and valuable diagnostic tool, particularly in hospitals in areas where methicillin-resistant S. aureus is endemic

Survey of Integron Types and Carbapenem Resistance Encoding Genes in Acinetobacter Baumannii Isolated from Burn Wound Samples

Introduction: Acinetobacter baumannii is one of the most important pathogenic bacteria that causes nosocomial infections, especially in burned patients. In recent years, Carbapenems have been considered as a selective antibiotic in the treatment of multi-drug resistant A. baumannii, but the rapid appearance of carbapenem-resistant A. baumannii has been reported worldwide. The purpose of this study was to investigate different classes of integron and Carbapenem-resistance encoding genes in A. baumannii isolated from burn wound samples in Shahid Motahari Hospital in Tehran. Material and Methods: In this descriptive cross-sectional study, 70 samples of A. baumannii were collected from burn injured patients referred to the Motahari Hospital. After identification and confirmation of strains, an antibiotic susceptibility test was performed using disk diffusion agar test. Also, metallo-β-lactamases producing isolates were identified using combined disk and E-test. BlaKPC producing strains were also identified using modified Hodge test. Finally, in order to evaluate genomic strains, after DNA extraction using boiling method, the PCR reaction for intI, intII, intIII, IMP, VIM, NDM, OXA-23-like, OXA-24-like, OXA genes -85-like, OXA-51-like and KPC. Results: In this study, all A. baumannii isolates were resistant to ciprofloxacin, cefotaxime, piperacillin and Trimethoprim/sulfamethoxazole. Out of 67 imipenem-resistant isolates, 57 (85.1%) and 61 (91%) isolates were considered as MBL producing in combination phenotypic tests and E-test. 44 (65.6%), 21 (31.3%) and 1 (1.5%) isolates were positive for blaVIM, blaIMP and blaNDM genes, respectively. So, 52 (77.6%) and 27 (40.3%) had OXA-23 and OXA-24 genes. 11 (15.7%) isolates were positive for KPC production in the Modified Hodge Test, but only 27.3% (3 strains out of 11 isolates) were carrying blaKPC gene. Also, 12 (17.1%), 54 (77.1) and 3 (4.3%) isolates, were carrying intI, intII and intIII genes, respectively. Conclusion: The increased frequency of carbapenem-resistant A. baumannii in burn patients suggests choosing an appropriate antibiotic regimen based on the antibiotic susceptibility pattern of the isolates. The rapid identification of carbapenemase-producing strains is helpful to select suitable options for antimicrobial therapy and prevent the further spread of their encoding genes

Genotypic characterization, invasion index and antimicrobial resistance pattern in Listeria monocytogenes strains isolated from clinical samples

Objective: To evaluate antimicrobial resistance, invasion index and genetic profile in Listeria monocytogenes isolated from clinical samples. Methods: At all, 170 clinical samples were collected from patients with spontaneous abortions hospitalized in Shariati hospital in Tehran during June 2010 to August 2013. Invasion index was determined using HeLa cells. The multiple-locus variable-number tandem-repeats analysis (MLVA) was used for evaluation of genetic relatedness. Results: Out of 14 L. monocytogenes isolates, 4 (28.57%), 2 (14.28%), 0 (0%), 5 (35.71%) and 3 (21.42%) were isolated from placental tissue, urine, blood, vaginal and rectal swabs, respectively. High resistance to penicillin and multidrug resistant were found amongst isolates. The invasion index was in the range of 0.001–0.007. Seven different types were obtained by MLVA assay and type 2 and 3 with 4 strains were the most frequent type. Strains isolated from the vagina and the placenta of the same type were also more resistant to penicillin. Conclusions: Since MLVA is a high-throughput screening method that is fairly inexpensive, easy to accomplish, rapid, and trustworthy, it is well suited to interlaboratory comparisons during epidemiological investigations. Also further studies of larger samples from a variety of sources such as food and animal specimens recommended comparing by MLVA method