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Copyright of Archives of Razi Institute is the property of Institut Razi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Gastrointestinal colonization of carbapenem-resistant Enterobacteriaceae (CRE) could serve as a reservoir for the transmission of these pathogens in the clinical setting. The aim of this study was to investigate the intestinal carriage of CRE and to analyze risk factors for CRE carriage. Rectal swabs were collected from 95 patients at two Iranian university hospitals. CRE screening was performed using selective media (CHROMagar and MacConkey agar). Polymerase chain reaction (PCR) was used to detect carbapenemase-encoding genes. Clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE). The rate of carriage of CRE in hospitalized patients was 37.9%. Overall, 54 CRE isolates were identified, of which 47 were carbapenemase-producers. All of the 54 CRE were detected using CHROMagar compared with 52 CRE detected using MacConkey agar. Fifteen patients were colonized by multiple CRE isolates. Three significant risk factors for CRE carriage were detected: intensive care unit (ICU) hospitalization, antibiotic exposure, and mechanical ventilation. bla was the most frequent carbapenemase detected, followed by bla and bla . Eleven carbapenemase-producing Enterobacteriaceae (CPE) isolates co-harbored bla and bla . Also, six CPE isolates co-harbored bla and bla . We did not detect bla , bla , bla , or bla . PFGE analysis showed that Escherichia coli clones were diverse, while Klebsiella pneumoniae isolates were divided into four clusters. Cluster I was the major clone carrying bla and bla genes. In our study, the carriage rate of CRE was high and the emergence of CPE isolates among patients is alarming. The implementation of adequate preventive measures such as active surveillance is urgently needed to control the spread of CPE in the healthcare setting. [ABSTRACT FROM AUTHOR]

Background and Objectives: Pseudomonas aeruginosa possesses a variety of virulence factors that may contribute to its pathogenicity. The aim of this study was to evaluate oprI, oprL and toxA genes for PCR identification of clinical P. aeruginosa. In order to find out any relation between special virulence factors and special manifestation of P. aeruginosa infections, we detected virulence factors among these isolates by PCR. Ribotyping was used to evaluate the clonal relationship between strains with the same genetic patterns of the genes studied. Materials and Methods: In this study, 268 isolates of P. aeruginosa were recovered from burn, wound and pulmonary tract infections. The prevalence of oprI, oprL, toxA, lasB, exoS and nan1 genes was determined by PCR. One hundred and four isolates were selected randomly to investigate clonal diversity of the isolates with ribotyping using SmaI. Results and Conclusions: All P. aeruginosa isolates in this study carried oprI, oprL and lasB genes. Difference between exoS prevalence in isolates from pulmonary tract and burn isolates was statistically significant. Prevalence of nan1 and toxA gene was significantly higher in pulmonary tract and burn isolates, respectively. Ribotyping showed that most of the isolates (87%) belonged to clone A and B. Detection of oprI, oprL and toxA genes by PCR is recommended for molecular identification of P. aeruginosa. Determination of different virulence genes of P. aeruginosa isolates suggests that they are associated with different levels of intrinsic virulence and pathogenicity. Ribotyping showed that strains with the same genetic patterns of the genes do not necessarily have similar ribotype patterns. [ABSTRACT FROM AUTHOR]

Rapid detection of carbapenemase-producing Enterobacteriaceae (CPE) is urgently needed to prevent their spread in healthcare settings. Here, we have evaluated the performance of the phenotypic methods for detection of carbapenemase production directly from bacterial cultures. A total of 99 clinical and rectal Enterobacteriaceae isolates were included (81 carrying known carbapenemase-encoding genes and 18 without carbapenemase production). All isolates were subjected to the five phenotypic tests including in-house Carba NP (iCarba NP), modified-Carba NP, E-Test MBL, modified Hodge test (MHT), and commercial combination disk test. Test results were read at different time points for iCarba NP and modified-Carba (1 min, 5 min, 15 min, 1 h and 2 h). The sensitivity and specificity of the iCarba NP were 78.87% and 100%, respectively, whereas those of the modified-Carba NP test were 95.06% and 94.44%, respectively. False-negative results were detected in four OXA-48 isolates with the use of modified-Carba NP, whereas one non-carbapenemase isolate had false-positive results. The sensitivity/specificity was 91.30%/100% and 80.25%/83.33% for the E-Test MBL and MHT, respectively. The sensitivity and specificity of the aminophenylboronic acid synergy test were 100% and 97.94%, respectively, whereas those of the dipicolinic acid synergy test were 82.61% and 96.23%, respectively. Rapid, simple, and reliable methods are needed for laboratory detection of CPE isolates to improve the detection and surveillance of these clinically relevant pathogens in an epidemiological context. We conclude that the modified-Carba NP test can be one of the reliable tests for the prediction of carbapenemase-producing bacteria.IMPORTANCEThe emergence of carbapenem resistance among Gram-negative bacteria is a serious global health threat. Here, we investigate the performance of the five phenotypic assays against carbapenemase-producing and carbapenemase-non-producing Enterobacteriaceae. Accurate and rapid detection of CPE isolates is critically required for clinical management and treatment of infections caused by these organisms. Among the five evaluated phenotypic tests, the mCNP test presented the highest sensitivity (95.06%) and, therefore, can be considered the best test to be used as a screening phenotypic methodology., Competing Interests: The authors declare no conflict of interest.

Background and Objectives: Leptospirosis is a zoonotic disease caused by pathogenic Leptospira serovars. The genus Leptospira cannot differentiated by conventional techniques. However, identity determination of pathogenic serovar is precious of public health problems and epidemiological studies. Pulsed-field gel electrophoresis facilitates rapid identification of Leptospires to the serovar levels., Materials and Methods: In this study, we employed PFGE to evaluate 28 Leptospira isolates, with animal, human and environmental origin, obtained from Razi Vaccine and Serum Research Institute of Karaj, Iran. PFGE patterns of 28 Leptospira serovars were generated using the Not I restriction enzyme in comparison with the lambda ladder., Results: Out of 28 serovars evaluated, we identified 22 different pulsed types, designated P1-P22. Out of 22 pulse groups, 3 were found to be a common type, but others were a single Type. Groups consisting of the common type were P3, P9, P14, and P16. The results showed that the discriminatory index of PFGE by Not I enzyme was 0.99, demonstrating heterogeneous differentiation among serovar members., Conclusion: The PFGE methodology used in this study showed excellent interlaboratory report usability, rapid, reliable, enabling standardization and data sharing between laboratories., (Copyright© 2024 The Authors. Published by Tehran University of Medical Sciences.)

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) infections are a major public health problem, necessitating the administration of polymyxin E (colistin) as a last-line antibiotic. Meanwhile, the mortality rate associated with colistin-resistant K. pneumoniae infections is seriously increasing. On the other hand, importance of administration of carbapenems in promoting colistin resistance in K. pneumoniae is unknown., Case Presentation: We report a case of K. pneumoniae-related pyogenic liver abscess in which susceptible K. pneumoniae transformed into carbapenem- and colistin-resistant K. pneumoniae during treatment with imipenem. The case of pyogenic liver abscess was a 50-year-old man with diabetes and liver transplant who was admitted to Abu Ali Sina Hospital in Shiraz. The K. pneumoniae isolate responsible for community-acquired pyogenic liver abscess was isolated and identified. The K. pneumoniae isolate was sensitive to all tested antibiotics except ampicillin in the antimicrobial susceptibility test and was identified as a non-K1/K2 classical K. pneumoniae (cKp) strain. Multilocus sequence typing (MLST) identified the isolate as sequence type 54 (ST54). Based on the patient's request, he was discharged to continue treatment at another center. After two months, he was readmitted due to fever and progressive constitutional symptoms. During treatment with imipenem, the strain acquired bla OXA-48 and showed resistance to carbapenems and was identified as a multidrug resistant (MDR) strain. The minimum inhibitory concentration (MIC) test for colistin was performed by broth microdilution method and the strain was sensitive to colistin (MIC < 2 µg/mL). Meanwhile, on blood agar, the colonies had a sticky consistency and adhered to the culture medium (sticky mucoviscous colonies). Quantitative real-time PCR and biofilm formation assay revealed that the CRKP strain increased capsule wzi gene expression and produced slime in response to imipenem. Finally, K. pneumoniae-related pyogenic liver abscess with resistance to a wide range of antibiotics, including the last-line antibiotics colistin and tigecycline, led to sepsis and death., Conclusions: Based on this information, can we have a theoretical hypothesis that imipenem is a promoter of resistance to carbapenems and colistin in K. pneumoniae? This needs more attention., (© 2024. The Author(s).)

Background: The investigation of the presence of extended-spectrum beta-lactamase (ESBL) within Enterobacteriaceae in both fecal carriers and patients is an essential matter. Furthermore, the assessment of distinct characteristics exhibited by resistant bacteria obtained from fecal carriers and patients, as well as the comparison of these characteristics between the two groups, could provide a deeper understanding of how the resistant isolates can remain concealed within a dormant reservoir and intensify antimicrobial resistance. The aim of the present study was to concentrate on the comparison of the antimicrobial resistance pattern and molecular features between strains obtained from clinical and carrier sources., Material and Methods: A total of 142 clinical samples and 120 rectal swabs were collected from June to October 2016. ESBL screening was performed using the double-disk synergy test. PCR was done for the detection of ESBL genes. Assessment of biofilm formation, virulence factor genes, and MLVA was performed for K. pneumonae isolates. Phylogroup typing was performed for E. coli isolates., Results: Of 146 samples, 67.6% were E. coli, and 32.4% were K. pneumoniae. The rate of bla CTXM-15 was 89.4%. In K. pneumoniae type D, ompk35 and fimH were the highest. All the K. pneumoniae isolates were classified into 12 mini clusters and the clinical isolates were characterized into 7 mini clusters. The phylogroup B2 in ESBL-EC was the highest (56.2%)., Discussion: Comparison of molecular characteristics and clonal relatedness between fecal carriers and patients showed noticeable relatedness and similarity which may indicate that ESBL-KP can be colonized with the same profiles in different settings and, therefore, may be widely distributed in both community and hospital settings. Therefore, implementation of control protocols, including surveillance of the fecal carriers, could impressively reduce silent reservoirs without clinical symptoms as well as patient rates., (© 2023. The Author(s).)

Backgrounds: The prevalence of infections associated with multi-drug resistant (MDR) Acinetobacter baumannii is increasing worldwide. Therefore, the introduction of effective vaccines against this bacterium seems necessary., Methods: AbOmpA and DcaP-like protein were selected as promising and putative immunogenic candidates based on previous in silico studies. Three formulations including AbOmpA, DcaP-like protein, and AbOmpA + DcaP-like protein were injected into C57BL/6 mice three times with Alum adjuvant. The specific production of IgG antibodies (e.g. total IgG, IgG1 and IgG2c) and cytokines (e.g. IL-4, IL-6, and IL-17A), were evaluated. LD50% of MDR A. baumannii ST2 Pas was measured using Probit's method. After the challenge with bacteria, a decrease in bacterial loads (DLs) in the lung and spleen of mice was measured. Then serum bactericidal assay was performed to determine the function of antibodies on day 42. In addition, histopathological examinations of the spleen and lung, the number of macrophage and neutrophil, as well as the rate of lymphocyte infiltration were assessed., Results: The highest level of total IgG was reported in the group immunized with DcaP-like protein on day 42. The survival rate of mice was 80% in the AbOmpA immunized group and 100% for the rest of two groups. DLs in the spleen of mice immunized with AbOmpA, DcaP-like protein, and combination form were 3.5, 3, and 3.4 Log 10 (CFU/g), respectively. While in the lung, the DLs were 7.5 Log 10 (CFU/g) for the AbOmpA group and 5 for the rest of two groups. The levels of IL-6, IL-4, and IL-17A were significantly decreased in all immunized groups after the bacterial challenge (except for IL-17A in the group of AbOmpA). The bactericidal effect of antibodies against DcaP-like protein was more effective. No histopathological damage was observed in the combination immunized group. The DcaP-like protein was more effective in neutrophil and macrophage deployment and decreased lymphocyte infiltration., Conclusion: The results of immunization with AbOmpA + DcaP-like protein induced a protective reaction against the sepsis infection of MDR A. baumannii. It seems that in the future, these proteins can be considered as promising components in the development of the A. baumannii vaccine., Competing Interests: Declaration of competing interest The authors have no conflict of interest to declare., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Pertussis also known as whooping cough is a respiratory infection in humans particularly with severe symptoms in infants and usually caused by Bordetella pertussis. However, Bordetella parapertussis can also cause a similar clinical syndrome. During 2012 to 2015, from nasal swabs sent from different provinces to the pertussis reference laboratory of Pasture Institute of Iran for pertussis confirmation, seven B. parapertussis isolates were identified by bacterial culture, biochemical tests, and the presence of IS1001 insertion in the genome. The expression of pertactin (Prn) as one the major virulence factor for bacterial adhesion was investigated using western blot. Moreover, the genomic characteristic of one recently collected isolate, IRBP134, from a seven-month infant was investigated using Illumina NextSeq sequencing protocol. The results revealed the genome with G+C content 65% and genome size 4.7 Mbp. A total of 81 single nucleotide polymorphisms and 13 short insertions and deletions were found in the genome compared to the B. parapertussis 12822 as a reference genome showing ongoing evolutionary changes. A phylogeny relationship of IRBP134 was also investigated using global B. parapertussis available genomes., (© 2022. The Author(s).)

Hypervirulent Klebsiella pneumoniae (hvKp) pathotype is emerging worldwide in pyogenic liver abscesses (PLAs). However, the role of virulence factors in pathogenicity remains unclear. On the other hand, the epidemiology of PLAs in Iran is unknown. From July 2020 to April 2022, bacterial species were isolated and identified from the drainage samples of 54 patients with PLAs. K. pneumoniae as the most common pathogen of pyogenic liver abscesses was identified in 20 (37%) of the 54 patients. We analyzed the clinical and microbiological characteristics of K. pneumoniae -related pyogenic liver abscesses. Antibiotic susceptibility testes and string test were performed. 16S rRNA, antibiotic resistance, and virulence genes were determined by polymerase chain reaction amplification. Clonal relatedness of isolates was identified by multilocus sequence typing. Virulence levels were assessed in the Galleria mellonella larval infection model. Four hvKp isolates (K1/K2) were found to be responsible for cryptogenic PLAs, and 16 classical K. pneumoniae isolates (non-K1/K2) were associated with non-cryptogenic PLAs. Three capsular serotype K1 strains belonged to sequence type 23 (ST23) and one K2 strain to ST65. Meanwhile, the non-K1/K2 strains belonged to other STs. ST231 was the most common strain among the classical K. pneumoniae strains. Compared with the non-K1/K2 strains, capsular serotypes K1/K2 strains were less resistant to antibiotics, had positive string test results, and had more virulence genes. In Galleria mellonella , a concentration of 10 6 colony-forming units of the K1 hvKp strain resulted in 100% death at 24 hours, confirming the higher virulence of the hvKp strain compared with cKp. K. pneumoniae isolates represented that the acquisition of any plasmid or chromosomal virulence genes contributes to pathogenicity and high prevalence in PLAs. Meanwhile, hvKp isolates with a specific genetic background were detected in cryptogenic PLAs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Sohrabi, Alizade Naini, Rasekhi, Oloomi, Moradhaseli, Ayoub, Bazargani, Hashemizadeh, Shahcheraghi and Badmasti.)

Background: Extended-spectrum beta-lactamase-producing enterobacteria (ESBL-PE) in carriers have become a global health problem. Using molecular typing techniques, including PFGE, could be useful to determine the source of bacterial dissemination. The current study aimed to investigate the intestinal carriage of ESBL-producing E. coli (ESBL-EC) and clonal relatedness among ESBL-EC isolated from hospitalized and outpatient fecal carriers in Iran., Methods: A total of 120 rectal swabs were collected; 50.8% (61/120) from intensive care unit (ICU) inpatients and 49.2% (59/120) from outpatients. MacConkey agar enriched with cefotaxime was used to screen the ESBL-EC. PCR assays were performed to detect ESBL and carbapenemase genes. Pulse-fields gel electrophoresis (PFGE) was performed to assess clonal relatedness., Results: Totally, 60.0% (72/120) were carrier for ESBL-EC. The rates of resistance against ceftazidime and cefepime were 90.2% (65/72) and 93.0% (67/72), respectively. The rates of bla CTX-M-15 , bla TEM , bla SHV , bla NDM-1 , bla OXA-48 and bla IMP was 90.2% (65/72), 50.0% (36/72), 5.5% (4/72), 4.1% (3/72), 4.1% (3/72) and 1.3% (1/72), respectively. Based on a cut-off 80%, 69 ESBL-EC isolates could be categorized in 10 mini-cluster and 47 isolates were considered as singletons., Discussion: High heterogeneity among isolates from ESBL-EC suggests that this bacterium probably has a different source of dissemination. Screening of carriers in hospitals and communities could help the infection control program in public health., (© 2022. The Author(s).)

Fecal carriage of multidrug-resistant Escherichia coli , particularly sequence type 131 (ST131), is becoming a global concern. This study aimed at determining the prevalence rate and molecular epidemiology of extended-spectrum β -lactamase-producing E. coli (ESBL-Ec), carbapenemase-producing E. coli (CPEc), ceftazidime/avibactam (CAZ/AVI)-resistant E. coli , and ST131 isolates in healthy fecal carriers in Tehran, Iran. Among 540 samples studied, 233 (43.1%) carried ESBL-Ec, with the majority (93.9%) harboring the bla CTX-M. The carriage rate of CPEc was 2.5% ( n  = 14/540), and bla NDM gene was the predominant carbapenemase gene. Most CPEc isolates ( n  = 11/14) was shown to be resistant to CAZ/AVI. Among ESBL-Ec/CPEc, 7.3% ( n  = 17/233) belonged to E. coli ST131 clone, which was identified by polymerase chain reaction and confirmed by multilocus sequence typing. The ST131 isolates genetically typed by pulsed-field gel electrophoresis were heterogeneous and four different plasmids were detected by plasmid typing, with the IncFIA/FIB being the major type. Our findings disclose that the presence of carbapenem-resistant ST131 isolates, which are also resistant to CAZ/AVI, contributes to the spread of resistant strains in the community. Therefore, screening and monitoring of such resistant clone in healthy people is necessary.

Background: Pertussis is a current contagious bacterial disease caused by Bordetella pertussis (Bp). Given the prevalence of pertussis, development of new vaccines is important. This study was attempted to evaluate the expression of main virulence factors (pertussis toxin [PTX], PRN [pertactin], and filamentous hemagglutinin [FHA]) from Bp predominant strains and also compare the expression of these factors in the outer membrane vesicles (OMVs) obtained from predominant circulating Bp isolate., Methods: The physicochemical features of the prepared OMVs were analyzed by electron microscopy and SDS-PAGE. The presence of the mentioned virulence factors was confirmed by Western blotting. BALB/c mice (n = 21) immunized with characterized OMVs were challenged intranasally with sublethal doses of Bp, to examine their protective capacity., Results: Electron microscopic examination of the OMVs indicated vesicles within the range of 40 to 200 nm. SDS-PAGE and Western blotting demonstrated the expression of all three main protective immunogens (PTX, PRN, and FHA), prevalent in the predominant, challenge, and vaccine strains, and OMVs of the predominant IR37 strain and BP134 vaccine strain. Significant differences were observed in lung bacterial counts between the immunized mice with OMV (30 CFU/lung) compared to the negative control group ((6 104 CFU/lung; p < 0.001). In mice immunized with OMVs (3 µg), the number of lungs recovered colonies after five days dropped at least five orders of magnitude compared to the control group., Conclusion: OMVs obtained from circulating isolates with the predominant profile may constitute a highly promising vaccine quality. They also can be proposed as a potential basic material for the development of new pertussis vaccine candidate.

Background: Carbapenemase-producing Klebsiella pneumoniae (CP-KP) is becoming extensively disseminated in Iranian medical centers. Colistin is among the few agents that retains its activity against CP-KP. However, the administration of colistin for treatment of carbapenem-resistant infections has increased resistance against this antibiotic. Therefore, the identification of genetic background of co-carbapenem, colistin-resistance K. pneumoniae (Co-CCRKp) is urgent for implementation of serious infection control strategies., Methods: Fourteen Co-CCRKp strains obtained from routine microbiological examinations were subjected to molecular analysis of antimicrobial resistance (AMR) using whole genome sequencing (WGS)., Results: Nine of 14 K. pneumoniae strains belonged to sequence type (ST)-11 and 50% of the isolates had K-locus type 15. All strains carried bla OXA-48 except for P26. bla NDM-1 was detected in only two plasmids associated with P6 and P26 strains belonging to incompatibility (Inc) groups; IncFIB, IncHI1B and IncFII. No bla KPC , bla VIM and bla IMP were identified. Multi-drug resistant (MDR) conjugative plasmids were identified in strains P6, P31, P35, P38 and P40. MIC colistin of K. pneumoniae strains ranged from 4 to 32 µg/ml. Modification of PmrA, PmrB, PhoQ, RamA and CrrB regulators as well as MgrB was identified as the mechanism of colistin resistance in our isolates. Single amino acid polymorphysims (SAPs) in PhoQ (D150G) and PmrB (R256G) were identified in all strains except for P35 and P38. CrrB was absent in P37 and modified in P7 (A200E). Insertion of ISKpn72 (P32), establishment of stop codon (Q30*) (P35 and P38), nucleotides deletion (P37), and amino acid substitution at position 28 were identified in MgrB (P33 and P42). None of the isolates were positive for plasmid-mediated colistin resistance (mcr) genes. P35 and P38 strains carried iutA, iucD, iucC, iucB and iucA genes and are considered as MDR-hypervirulent strains. P6, P7 and P43 had ICEKp4 variant and ICEKp3 was identified in 78% of the strains with specific carriage in ST11., Conclusion: In our study, different genetic modifications in chromosomal coding regions of some regulator genes resulted in phenotypic resistance to colistin. However, the extra-chromosomal colistin resistance through mcr genes was not detected. Continuous genomic investigations need to be conducted to accurately depict the status of colistin resistance in clinical settings., (© 2021. The Author(s).)

Here we investigated nationwide clinical Bordetella pertussis isolated during 2005-2017 from different provinces of Iran, a country with more than 50 years whole cell vaccine immunisation history. Our results revealed the ongoing increase in the population of ptxP3/fim3-2 B. pertussis isolates in different provinces which were differentiated into nine clades. The largest clade (clade 8) which was previously found to be prevalent in Tehran was also prevalent across the country and clade 5 with ptxP3/prn9 genotype has also increased in frequency (14% of all ptxP3 isolates) in recent years. Furthermore, we detected the first ptxP3 B. pertussis isolates that does not express filamentous hemagglutinin (FhaB) as one of the major antigens of the pathogen and a key component of the acellular pertussis vaccine., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Hypervirulent Klebsiella pneumoniae (hvKp) has emerged as a pathogen of global concern. In this study, both phenotypic and genotypic tests were used to detect hvKp. Antimicrobial resistance profiles and clonal relatedness of clinical isolates were also determined. We found that 34.2% (163/477) of the isolates were tellurite resistant, and among them 102 hvKp isolates detected with iucA or iutA or peg-344 as molecular markers. The bla SHV (80.4%), followed by bla CTX-M-15 (76.5%) and bla TEM (67.6%), bla OXA-48 (53.9%), and bla NDM-1 (32.3%) were detected, while bla KPC-1 was not present in any hvKp isolates. It was found that the majority of hvKp isolates belonged to capsular serotype K20 and ompK36 group C, which is related to clonal group (CG) 23 (e.g. ST23). A high percentage of multidrug-resistant hvKp (76.6%) and high resistance to imipenem (67%) indicated a serious problem that should be addressed in the clinical setting., (© 2021. The Author(s).)

Background: Bordetella pertussis , a highly contagious respiratory. Notably, the resurgence of pertussis has recently been associated with the lacking production of vaccine virulence factors. This study aimed to screen pertactin (Prn) and filamentous hemagglutinin (Fha) production in Iran with 50 years' whole cell vaccine (WCV) immunization program., Methods: Overall, 130 B . pertussis isolates collected from Pertussis Reference Laboratory of Iran during 2005-2018. Real-time PCR was performed by targeting IS481, ptxP, IS1001 and IS1002 for species confirmation of B. pertussis . Western-blot was used to evaluate the expression of virulence factors (pertactin and filamentous hemagglutinin)., Results: All tested B. pertussis isolates expressed Prn and all except two isolates expressed Fha. We have sequenced genomes of these strains and identified differences compared with genome reference B. pertussis Tohama I., Conclusion: Many countries reporting Prn and Fha-deficiency due to acellular vaccine (ACV) pressure. Our results demonstrate in a country with WCV history, Fha-deficient isolates may rise independently. However, Prn-deficient isolates are more under the ACV pressure in B. pertussis isolates. Continues surveillance will provide a better understanding of the effect of WCV on the evolution of the pathogen deficiency., Competing Interests: Conflict of interest The authors declare no conflicts of interest., (Copyright © 2021 Saedi et al. Published by Tehran University of Medical Sciences.)

Background: Pertussis remain a global health concern, especially in infants too young to initiate their vaccination. Effective vaccination and high coverage limit the circulation of the pathogen, yet duration of protection is limited and boosters are recommended during a lifetime. In Iran, boosters are given at 18 months and 6 years old using whole pertussis vaccines for which efficacy is not known, and pertussis surveillance is scant with only sporadic biological diagnosis. Burden of pertussis is not well understood and local data are needed., Methods: Hospital-based prospective study implementing molecular laboratory testing in infants aged ≤6 months and presenting ≥5 days of cough associated to one pertussis-like symptom in Tehran. Household and non-household contact cases of positive infants were evaluated by comprehensive pertussis diagnosis (molecular testing and serology) regardless of clinical signs. Clinical evaluation and source of infection were described., Results: A total of 247 infants and 130 contact cases were enrolled. Pertussis diagnosis result was obtained for 199 infants and 104 contact cases. Infant population was mostly < 3 months old (79.9%; 157/199) and unvaccinated (62.3%; 124/199), 20.1% (40/199) of them were confirmed having B. pertussis infection. Greater cough duration and lymphocyte counts were the only symptoms associated to positivity. Half of the contact cases (51.0%; 53/104) had a B. pertussis infection, median age was 31 years old. A proportion of 28.3% (15/53) positive contacts did not report any symptom. However, 67.9% (36/53) and 3.8% (2/53) of them reported cough at inclusion or during the study, including 20.8% (11/53) who started coughing ≥7 days before infant cough onset. Overall, only five samples were successfully cultured., Conclusion: These data evidenced the significant prevalence of pertussis infection among paucy or poorly symptomatic contacts of infants with pertussis infection. Widespread usage of molecular testing should be implemented to identify B. pertussis infections.

Background and Objectives: Escherichia coli (E. coli) sequence type 131 (ST131) is associated with extended-spectrum beta-lactamase (ESBL) production and fluoroquinolone resistance. This study aimed to investigate the prevalence of ST131, ESBL, and plasmid-mediated quinolone resistance (PMQR) genes in the ciprofloxacin-resistant (CIP R ) and ESBL producers from women with UTI., Materials and Methods: The CIP-resistant ESBL producing (CIP R /ESBL + ) E. coli isolates were screened for ST131-by specific PCR of mdh and gyrB . The ESBL and PMQR genes were screened by single PCR. The ST131 and non-ST131 isolates were selected to determine the mutations of gyrA and parC using PCR and sequencing, and also their genetic background by the Pasteur-MLST scheme., Results: Overall, 55% (33/60) CIP R /ESBL + isolates were identified as ST131 (94% O25b-ST131). Resistance rate to ampicillin-sulbactam (70%), aztreonam (97%) and gentamicin (61%), the prevalence of aac(6')-Ib-cr (66%), bla CTX-M-15 (82%), the profile of qnrS+aac(6')-Ib-cr (30%), and the double mutation in the parC was significantly higher in ST131 than non- ST131 isolates. The coexistence of PMQR and ESBL genes was found in more than 50% of ST131 and non-ST131 isolates. ST131 isolates differentiated into PST43 and PST506., Conclusion: Management of women with UTI caused by the CIP R /ESBL + isolates (ST131) co-harbored PMQR, ESBL, and chromosomal mutations, is important for their effective therapy., (Copyright © 2021 The Authors. Published by Tehran University of Medical Sciences.)

Classical (CKp) and hypervirulent (hvKp) Klebsiella pneumoniae are two different circulating pathotypes. The aim of this study was to assess the prevalence, epidemiology and molecular relatedness of hvKps using a systemic review and meta-analysis. The data extracted from Medline, Embase, and Web of Science and finally 14 studies met the eligible criteria. To combine prevalence proportions of all studies, we performed the metaprop command embedded in the Meta package software. Totally, of 1814 K. pneumoniae isolates, 21.7% (394/1814) were hvKp. The molecular typing showed that all hvKp isolates were grouped into 50 different sequence types (STs) of them ST23, ST11, ST65 and ST86 were common. K1, K2 and K64 were dominant capsule serotypes that strongly related to ST23, ST65 and ST11, respectively. It seems that clonal group 23 (CG23) is associated with liver abscess and CG11 related to various clinical sources., (Copyright © 2021 The Authors. Published by Tehran University of Medical Sciences.)

Escherichia coli serogroup O25b-sequence type 131 ( E. coli O25b/ST131) is known as a multidrug-resistant organism with high virulence potential and has received attention internationally. We aim to investigate the prevalence of O25b/ST131 and the distribution of bla CTX-M-15 , pathogenicity island (PAI) markers, phylogenetic groups, and H-antigen typing in the E. coli O25b/ST131 isolated from patients with urinary tract infection (UTI) in Tehran, the capital of Iran. Seventy (26.9%) E. coli isolates were identified as O25b/ST131. There was also a significant difference in the prevalence of virulence genes, including papA , sfa , sat , cnf1 , iutA , kpMII , traT, and usp , in the O25b/ST131 isolates rather than non-O25b/ST131 ones ( p ≤ 0.05). Furthermore, 78% of the O25b/ST131 isolates carried four to seven PAIs, while 71% of non-O25b/ST131 isolates carried two to four PAI markers ( p ≤ 0.05). Our study showed that in addition to H4, other H-antigens may play a role in the O25b/ST131 virulence potential. Besides, a significant association was found between the history of previous UTIs and infection among the O25b/ST131 clone isolates. Pulsed-field gel electrophoresis revealed circulating of O25b:H4-ST131/PST43 clone in both hospital and community. Approximately one in every three uropathogenic E. coli isolates was the O25b/ST131 clone, representing a significant public health threat. Practical investigation on O25b/ST131 can be helpful in better understanding of ST131 evolution and controlling UTI in hospitals.

Background: Outer membrane vesicles (OMVs) release from Gram-negative bacteria and are interesting alternatives that can replace those vaccines that contain naturally incorporated bacterial surface antigens, lipopolysaccharides (LPS) and outer membrane proteins (OMPs). Nanoparticles can be used to encapsulate vesicles for slow release and prevent macromolecular degradation., Objective: Therefore, encapsulation of OMVs of B. pertussis into sodium alginate nanoparticles was the main aim of the current study., Methods: The OMVs of B. pertussis extracted and characterized by particle sizer, electron microscopy, SDSPAGE and Western blot assays. The extracted OMVs were encapsulated in sodium alginate nanoparticles (OMV-NP) using unique gelation process and injected into BALB/c mice. Immunogenicity indices such as different classes of antibodies and interleukins related to different T cell lines were evaluated in immunized mice by ELISA. The respiratory challenge was evaluated in the groups of mice. The existence of pertussis toxin (PTX), filamentous haemagglutinin (FHA) and PRN (pertactin) in B. pertussis OMVs was verified using SDSPAGE and Western blot analysis., Results: TEM electron microscopy showed the size of these OMVs to be around 20-80 nm. The OMVs with appropriate quality were encapsulated into sodium alginate nanoparticles (OMV-NP), and the final size was about 500 nm after encapsulation. Immunity indices were significantly higher in the OMV-NP receiving group. In challenge tests, the OMV-NP vaccine was able to show the highest rate of lung clearance compared to the control groups (OMV and wPV) at the lowest injection dose., Conclusion: The results indicate the potential of OMV-NP as a novel vaccine delivery system., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Cholera, a life-threatening disease caused by the Gram-negative bacterium Vibrio cholera, remains a concern in developing countries. The present study investigated the immunogenicity and protective immunity of outer membrane vesicles (OMVs) and combination of OMV and killed whole cells (WC) of a local strain isolated from the last outbreak in Iran in addition to reference and local strains of V. cholerae El Tor O1 in comparison to Dukoral vaccine in mice model. The protein content, morphology, and size of extracted OMVs were evaluated by electrophoresis and microscopic analyses, respectively. The serum titers of total immunoglobulin G (IgG), IgG1, IgG2a, and immunoglobulin A (IgA) in addition to secretory IgA and total IgG in different mice groups were determined by enzyme-linked immunosorbent assay (ELISA). In addition, fluid accumulation (FA) assay regarding the resistance to live strain of V. cholerae in ligated ileal loops was carried out to determine immunogenicity by OMV or combination of OMV and WC in comparison to that reported for Dukoral vaccine. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified OMVs indicated protein profiles within the range of 34-52 kDa. Furthermore, transmission electron microscopy demonstrated the spherical shaped vesicles of 50-200 nm. The results of ELISA showed significant titers of systemic and mucosal immune anti-OMV IgGs in immunized BALB/c mice with different vaccine regimens. Additionally, a notable increase in the FA ratio was demonstrated in this study. The obtained results of the present study revealed that the WC-OMV combination of local strain can induce a high level of antibody response indicating more protection than OMV or WC separately. Moreover, it can be considered an effective immunogen against V. cholerae., (Copyright © 2021, Author(s). Published by Kowsar.)

Carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKp) has been increasingly reported and is now recognized as a public health concern. The aim of this study was to investigate the molecular epidemiology of CR-hvKp strains that were isolated from an Iranian hospital. A total of 74 non-duplicated carbapenem-resistant K. pneumoniae (CR-Kp) were collected from patients' clinical or surveillance cultures. Resistance/virulence genes were identified by PCR and sequencing. String test, capsular genotyping, conjugation assays, PCR-based replicon typing, pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and were performed. All 74 CR-Kp isolates were carbapenemase producers, which co-carried multiple resistance genes such as bla CTX-M-15 , bla TEM-1 , bla SHV-type , qnrB1, and qnrS1. The most common carbapenemase gene was bla OXA-48 (67/74 90.5%), followed by bla NDM-1 (18/74 24.3%), and bla NDM-7 (3/74 4%). The bla OXA-48 and bla NDM-1 were found on IncL/M and IncFII conjugative plasmids, respectively. Of 74 CR-Kp isolates, 49 were positive for string test. Capsular genotyping revealed that 34 and 10 CR-Kp strains belonged to the K1 and K2 serotypes, respectively. rmpA was the most prevalent virulence gene detected in 64.8% of the isolates. Fifty two strains were identified as CR-hvKp. PFGE typing showed 5 different clusters with two major clusters B (39 isolates, 52.7%) associated with sequence type 11 (ST11), and A (21 isolates, 28.4%) associated with ST893. Furthermore, ST147, ST392, and ST15 carbapenemase producers have also been sporadically identified. One isolate belonging to ST11 was resistant to colistin and were negative for mcr-1-2-3 genes. Insertional inactivation of mgrB due to IS elements was observed in the colistin-resistant isolate. Our findings suggest that ST11 CR-hvKP strain has a clonal distribution in our hospital. Therefore, immediate implementation of infection-control measures may be the best way to prevent the spread of these clones., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Botulism is a severe neuroparalytic disease caused by toxins produced by several Clostridium species. This work presents the surveillance results of botulism in Iran, with the distribution of the cases by regions and by vehicle of transmission., Methods: We describe the findings of the Centers for Disease Control and Prevention (CDC) surveillance on 2037 suspected cases of food-borne botulism during 2007-2017., Results: A total of 252 (12.3%) cases were confirmed to food-borne botulism. The mean annual incidence per 100,000 Iranian Natives was 7.1 cases for male individuals and 3.3 cases for female individuals. All botulism events were confirmed to be foodborne. The most commonly implicated food was home-prepared traditional processed fish product, followed by the consumption of commercially canned products and non-pasteurized dairy products. Forty-eight (19%) fatal botulism were reported which, the case-fatality rate declined from 4.5% to 0.7% during the study period., Conclusion: Laboratory-based diagnosis of botulism is an imperative procedure to elucidate cases, particularly food-borne botulism, to identify toxins in food and confirm clinical diagnosis, helping sanitary control measures. In addition, educational materials related to botulism prevention should be disseminated to different communities., Competing Interests: The authors declare they have no conflicts of interest., (© 2020 Atlantis Press International B.V.)