Acinetobacter baumannii is an important human pathogen responsible for a various type of infections. These bacterial strains are generally resistant to numerous antibiotics. Therefore, eradication of such strains is problematic and related to high mortality. We investigated the effect of cyanide 3-chlorophenylhydrazone (CCCP) efflux pump inhibitor in tigecycline-resistant strains of Acinetobacter baumannii. In a cross-sectional study, from July until the end of February 2017, eighty isolates of A. baumannii were recovered. Antimicrobial susceptibility testing against tigecycline was performed by the disc diffusion method and determination of minimum inhibitory concentration by broth microdilution method, according to Clinical and Laboratory Standards Institute guidelines. Active efflux pumps were detected by CCCP as an efflux pumps inhibitor, and the gene expression of some of the resistance/nodulation/division (RND)-type efflux pumps was measured by semiquantitative RT-PCR (qRT-PCR). Antibiotic susceptibility tests in this study showed that 78 of 80 A. baumannii isolates were resistant to tigecycline. The results of phenotypic detection of efflux pumps revealed that 23.07% of tigecycline-resistant A. baumannii isolates can contain active efflux pumps. On the basis of conventional PCR, genes coding for adeF and adeJ were detected in 76 (98%) A. baumannii isolates. The results of qRT-PCR showed that the transcript level of the adeJ gene increased in 66.6% A. baumannii isolates with CCCP-positive tests and was correlated with tigecycline resistance. The results of this study indicate that RND-type efflux pumps appear to play a significant role in the tigecycline resistance of A. baumannii.

Systematic evaluation of household contacts of persons with pulmonary tuberculosis (TB) in low- and middle-income countries is recommended by the World Health Organization (WHO). This study recruited adult household contacts of diagnosed TB patients in two high burden provinces of Iran to estimate the prevalence and incidence of active disease and latent TB infection (LTBI) among individuals exposed to TB cases. We conducted a cohort study among adults in household contact with a pulmonary TB index case. All subjects were assessed for active disease through evaluation of symptoms. Tuberculin skin test (TST) and QuantiFERON®-TB Gold Plus (QFT-Plus) were used to define LTBI. These tests were performed at the time of the index TB case diagnosis and repeated if the previous result was negative, at three-, 12-, and 18-months post recruitment. In addition, interferon-γ-induced protein-10 (IP-10) concentrations were measured in QFT-Plus supernatants for all participants three months after diagnosing the index case. A total of 451 individuals who had close contact with 95 active TB patients were enrolled in this study. Five (1.1%) contacts were diagnosed with active TB and 285 (63.2%) were identified with LTBI during our study. The incidence rate of LTBI among adult household contacts of TB index cases was 0.44 per person per year. The overall rate of LTBI was high. Systematic screening of all household contacts of pulmonary TB should be expanded in Iran to make the timely achievement of the global end TB strategy feasible.

Carbapenem is a broad-spectrum beta-lactam antibiotic considered the last choice for the treatment of antibiotic-resistant Gram-negative bacteria. Thus, the increasing rate of carbapenem resistance (CR) in Enterobacteriaceae is an urgent public health threat. This study aimed to evaluate the antibiotic susceptibility pattern of carbapenem-resistant Enterobacteriaceae (CRE) to new and old antibiotics. In this study, Klebsiella pneumoniae, E. coli, and Enterobacter spp. were collected from 10 hospitals in Iran for one year. CRE is recognized by resistance to meropenem and/or imipenem disk after identification of the collected bacteria. Antibiotic susceptibility of CRE against fosfomycin, rifampin, metronidazole, tigecycline, and aztreonam was detected by disk diffusion method and colistin by MIC. In this study, 1222 E. coli, 696 K. pneumoniae, and 621 Enterobacter spp. were collected from 10 hospitals in Iran in one year. Fifty-four E. coli (4.4), 84 K. pneumoniae (12), and 51 Enterobacter spp. (8.2) were CRE. All CRE strains were resistant to metronidazole and rifampicin. Tigecycline has the highest sensitivity on CRE and levofloxacin for Enterobacter spp. Tigecycline showed an acceptable effectiveness rate of sensitivity on the CRE strain. Therefore, we suggest that clinicians consider this valuable antibiotic to treat CRE.

NDM-1 producing gram-negative bacteria can be resistant to every beta-lactam antibiotic, including carbapenem which is one of the last-lines of antibiotic therapy against multi-drug resistant bacteria. This study aimed to detect the metallo-beta-lactamase in the isolated gram-negative bacteria of the Iranian clinical specimens collected from two major cities in Iran. In this cross sectional study 171 Acinetobacter baumannii, 120 Enterobacter spp. and 145 Klebsiella pneumoniae isolated from clinical specimens of two training hospitals in Tabriz and Mashhad were evaluated. Carbapenem resistant screening was performed according to CLSI guide line. The antibiotic susceptibility testing was prepared for carbapenem resistant strains. Then, the metallo-beta- lactamase genes detection was also carried out by PCR assay and confirmed by sequencing. Sixty-eight, 12 and 22 carbapenem resistant Acinetobacter baumannii, Klebsiella pneumoniae and Enterobacter spp. were respectively confirmed, respectively. blaVIM in 9% and blaNDM-1 in 4% of isolated A. baumannii were observed. blaNDM-1 was also detected in 18% and 25% of K. pneumoniae and Enterobacter spp. isolates, respectively. This is the first report of NDM-1 producer A. baumannii and Enterobacter pp. in Iran. NDM-1 producing gram-negative bacteria can be resistant to all beta-lactam antibiotics and cause complicated challenges in health care systems.

Background: The spread of resistant bacteria has caused serious concern worldwide. The spread of multidrug-resistant (MDR) and extensive drug-resistant (XDR) limits the choice of antibiotics, making available antibiotics less effective. Objectives: This study aimed to investigate resistance patterns to seven global threatening organisms announced by the Centers for Disease Control and Prevention (CDC) for one year in Iran, called ESKAPE bacteria (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.). Methods: Clinical isolates were collected from 10 selective hospitals in nine provinces. Antibiotic susceptibility testing was performed according to the Clinical and Laboratory Standards Institute for each bacterium. Results: A total of 5522 bacterial species were considered, of which 30% were ESKAPE. Multidrug-resistant A. baumannii and Staphylococcus aureus methicillin-resistant Staphylococcus aureus (MRSA) were the most identified in Gram-negative and -positive bacteria, with the frequency of 44% and 39%, respectively. The remaining bacteria, including E. coli, K. pneumoniae, Enterobacter spp. P. aeruginosa, and Enterococcus spp., had the frequency of 30%, 32%, 21%, 20%, and 22%, respectively. Conclusions: The determined patterns for the antibiotic resistance of the ESKAPE bacteria can help determine antibiotic stewardship. Also, the high rates of the ESKAPE bacteria in Iran could be alarming for healthcare centers not to misuse broad-spectrum antibiotics.

Background: Rattus norvegicus are reservoirs for transmission of various zoonotic parasites, and they have become a threat to public health worldwide. Given the large number and the significant presence of R. norvegicus throughout the city of Tehran, this study aims to assess the frequency of zoonotic parasites carried by commensal rodents wandering in Tehran, Iran. The study considered the north, south, west, east, and center regions of Tehran for the purposes of this study. The serological tests were applied in order to detect effective antibodies against Trichomonas vaginalis (T. vaginalis), Babesia spp., and Cryptosporidium spp. using a commercial qualitative rat ELISA kit. The frequency of Toxoplasma gondii (T. gondii) was surveyed by using the conventional PCR method. Furthermore, nested PCR was employed to detect the presence of Giardia spp. and Leishmania spp. in commensal R. norvegicus dispersed in Tehran. Results: Approximately, 76% of the 100 R. norvegicus tested were infected with at least one zoonotic parasite, indicating the significant frequency of parasites within the study areas. Seroreactivity against T. vaginalis, Babesia spp., and Cryptosporidium spp. was detected in 5%, 0%, and 1% of the R. norvegicus tested, respectively. T. gondii DNA was detected in 32 out of 100 (32%) R. norvegicus. In addition, Leishmania spp. and Giardia spp. DNA were found in 18 out of 100 (18%) and 76 out of 100 (76%) R. norvegicus investigated, respectively. T. vaginalis with 15% and T. gondii with 70% had the highest frequency of parasites among the R. norvegicus collected from the western and northeastern regions of Tehran, respectively. Moreover, Giardia spp. with 95% and Leishmania spp. with 30% had the highest frequency in the east and center districts, respectively. Conclusion: The findings showed a wide geographical dissemination of Giardia spp., Toxoplasma gondii, and Leishmania spp. in R. norvegicus within five districts of Tehran. In contrast, other parasites such as Cryptosporidium spp. infection were rarely detected in Rattus populations. No evidence for the circulation of Babesia spp. was found in this study.