First report of OXA-48-producing Klebsiella pneumoniae strains in Iran

Intestinal Carriage of Carbapenemase-Producing Enterobacteriaceae Members in Immunocompromised Children During COVID-19 Pandemic

Background: Hospital-acquired infection with carbapenem-resistant Enterobacteriaceae (CRE) is a global concern. The administration of antibiotics among the infected and non-infected immunocompromised children with SARS-CoV-2 is associated with an increased risk of intestinal CRE colonization and bacteremia during hospitalization. Objectives: The present study aimed to detect the correlation between the intestinal colonization of carbapenemase encoding Enterobacteriaceae with SARS-CoV-2 infection and antibiotic prescription among immunocompromised children admitted to the oncology and Bone Marrow Transplantation (BMT) wards. Methods: Stool samples were collected from the immunocompromised children, and the members of Enterobacteriaceae were isolated using standard microbiological laboratory methods. Carbapenem resistance isolates were initially characterized by the disc diffusion method according to CLSI 2021 and further confirmed by the PCR assay. SARS-CoV-2 infection was also recorded according to documented real-time PCR results. Results: In this study, 102 Enterobacteriaceae isolates were collected from the stool samples. The isolates were from Escherichia spp. (59/102, 57.8%), Klebsiella spp. (34/102, 33.3%), Enterobacter spp. (5/102, 4.9%), Citrobacter spp. (2/102, 1.9%), and Serratia spp. (2/102, 1.9%). The carbapenem resistance phenotype was detected among 42.37%, 73.52%, 40%, 50%, and 100% of Escherichia spp., Klebsiella spp., Enterobacter spp., Citrobacter spp., and Serratia spp., respectively. Moreover, blaOXA-48 (49.1%) and blaNDM-1 (29.4%), as well as blaVIM (19.6%) and blaKPC (17.6%) were common in the CRE isolates. SARS-CoV-2 infection was detected in 50% of the participants; however, it was confirmed in 65.45% (36/55) of the intestinal CRE carriers. The administration of antibiotics, mainly broad-spectrum antibiotics, had a significant correlation with the CRE colonization in both the infected and non-infected children with SARS-CoV-2 infection. Conclusions: Regardless of the COVID-19 status, prolonged hospitalization and antibiotic prescription are major risk factors associated with the CRE intestinal colonization in immunocompromised children.

High Prevalence of blaOXA-48 and blaNDM-Producing Carbapenem-Resistant Klebsiella pneumoniae Isolated from Clinical Samples in Shahid Rajaei Hospital in Tehran, Iran

Background: Due to the increasing antibiotic resistance, treating infections caused by Klebsiella pneumoniae has become more challenging. Objectives: The present study aimed to investigate the prevalence of blaOXA-48 and blaNDM producing carbapenem-resistant K. pneumoniae isolated from clinical samples in Shahid Rajaei hospital in Tehran, Iran. Methods: Various clinical samples were collected from 1,186 patients admitted with open heart surgery in two wards (ICU and surgery) in Shahid Rajaei Heart Hospital in Tehran, Iran. Klebsiella pneumoniae isolates were identified by standard microbiologic tests. Antimicrobial susceptibility of isolates were determined by disk diffusion and E-test methods. A modified carbapenem inactivation method (mCIM) was performed to detect the presence of carbapenemase. Antibiotic resistance genes were detected using conventional polymerase chain reaction (PCR) by primers targeting blaOXA-48, blaSPM, blaIMP, blaVIM, and blaNDM genes. Results: A total of 131 clinical isolates of K. pneumoniae were isolated and 45.8% (60/131) of them were resistant to carbapenem. Klebsiella pneumoniae isolates showed the highest resistance rate (100%) to ceftriaxone, ceftazidime, cefazolin, and cefepime and the maximum sensitivity to tigecycline (96.7%). The carbapenemase-encoding blaOXA-48 and blaNDM-1 genes were detected in 96.7% and 66.7% of isolates, respectively. Eight different clusters of the isolates, considering a ≥ 80% homology cut-off, were shown with the same rep-PCR pattern. Clusters A, B, C, D, E, F, G, and H included 20, 11, 7, 6, 6, 3, 2, and 2 members, respectively. Conclusions: The RAPD-PCR method reveals the clonal relationship between isolates and may help improve infection control procedures.

Evaluate the Modified Carbapenem Inactivation Method for Phenotypic Detection of Carbapenemase Production Among Gram-Negative Bacteria

Background: Global growing infections by multi-drug resistance (MDR) or extensively drug-resistant (XDR) bacteria are a serious public health problem which can increase the rate of mortality and morbidity even in children. Carbapenem is the last choice therapy in case of antibiotic-resistant bacteria presence. Objectives: This study aimed to evaluate the easy to use method to identify carbapenemase producing bacteria which include in CLSI. Methods: In this descriptive study, 125 carbapenem-resistant and 97 carbapenem-susceptible gram-negative bacteria were included. PCR was used to identify carbapenemase enzymes include VIM, IMP, KPC, NDM-1, SPM-1, OXA-48 as a gold standard method. The modified carbapenem inactivation method (mCIM) was employed to phenotypically identify carbapenemase-producing bacteria. Some modifications were made to the CLSI proposed mCIM to ensure more accurate results in contrast of PCR. Results: The OXA-48 is the most prevalent detected carbapenemase and SPM-1 was not detected in any of strain. The results of the mCIM according to CLSI guide line demonstrated 100% sensitivity to define carbapenemase-producing bacteria. However, in the cases of non-carbapenemase-producing bacteria, only 4% of mCIM test results were consistent with the outcome of PCR. Decrease of the incubation time and the consider 15mm as a break point could increase the accuracy of mCIM against PCR. Conclusions: The results of this study endorse that mCIM test is a valuable method to detect carbapenemase producing bacteria if the three hours consider instead of 4 hours with 15mm break point.

Coexistence of aminoglycoside resistance genes in CTX-M-producing isolates of Klebsiella pneumoniae in Bushehr province, Iran

Background and Objectives:

Increasing the rate of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has given rise to a major healthcare issue in clinical settings over the past few years. Treatment of these strains is hardly effective since the plasmid encoding ESBL may also carry other resistance genes including aminoglycosides. The current study aimed to evaluate the prevalence of ESBL-producing K. pneumoniae and investigate the coexistence of Cefoxitamase-Munich (bla_CTX-M) with aminoglycoside-modifying enzyme (AME) genes, aac(3)IIa as well as aac(6′)Ib, in CTX-M-producing K. pneumoniae isolated from patients in Bushehr province, Iran.

Materials and Methods:

A total of 212 K. pneumoniae isolates were collected and confirmed using polymerase chain reaction (PCR) of the malate dehydrogenase gene. Isolates were screened for production of ESBL. Phenotypic confirmatory test was performed using combined disk test. The genes encoding CTX-M groups and AME genes, aac(3)IIa and aac(6′)Ib, were investigated by PCR.

Results:

The ESBL phenotype was detected in 56 (26.4%) K. pneumoniae isolates. Moreover, 83.9% of ESBL-producing isolates carried the genes for CTX-M type β-lactamases, which were distributed into the two genetic groups of CTX-M-1 (97.8%)- and CTX-M-2 (2.1%)-related enzymes. Notably, among K. pneumoniae isolates containing the bla_CTX-M gene, 68.08% of isolates harbored AME genes. In addition, the coexistence of bla_CTX-M with aac(3)-IIa and aac(6′)-Ib was observed in 46.8% of CTX-M-producing K. pneumoniae isolates.

Conclusion:

This study provides evidence of a high prevalence of AME genes in CTX-M-producing K. pneumoniae isolates; therefore, in the initial empirical treatment of infections caused by ESBL-KP in regions with such antibiotic resistance patterns, aminoglycoside combination therapy should be undertaken carefully.

Multicentre study of the main carbapenem resistance mechanisms in important members of the Enterobacteriaceae family in Iran

Resistance to carbapenems has been increasingly reported from the Enterobacteriaceae family, with different mechanisms in different geographic parts of the world. This study investigated the mechanisms of carbapenem resistance in Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. carried out as a multicentre study (n = 10). All third-generation cephalosporin-resistant E. coli, K. pneumoniae and Enterobacter spp. that had been recovered from the selected provinces were included. Modified Hodge test and Carba NP test were done as a phenotypical method for detection of carbapenemase; the most common carbapenemase was detected by PCR. We evaluated the presence of an active efflux pump by using cyanide 3-chlorophenylhydrazone. Overexpression of AcrA/B and presence of OqxAB was detected by real-time PCR and conventional PCR respectively. Microorganisms in this study included 58 E. coli, 95 K. pneumoniae and 60 Enterobacter spp. Modified Hodge test showed a sensitivity of 41% and a specificity of 83%, and the Carba NP test showed a sensitivity of 26% and a specificity of 92% for detection of carbapenemase. OXA-48 was the most frequently detected carbapenemase, followed by NDM-1. Thirty-nine percent and 27% of positive cyanide 3-chlorophenylhydrazone test organisms included active AcrA/B and OqxAB efflux pumps respectively. The result showed the Carba NP test was more specific than MHT. Data confirmed the involvement of AcrA/B and OqxAB efflux pump as a carbapenem resistance mechanism in selected bacteria. Similar to other reports from the Middle East, we found OXA-48 and NDM-1 to be the most frequent carbapenemase.

Dissemination Pattern of Multidrug Resistant Carbapenemase Producing Klebsiella pneumoniae Isolates Using Pulsed-Field Gel Electrophoresis in Southwestern Iran

Background

Klebsiella pneumoniae is an important cause of healthcare-associated infection. Carbapenemases have increasingly been reported in Enterobacteriaceae, especially in K. pneumoniae.

Propose

The objective of this study was to determine antibiotic resistance patterns, and the molecular epidemiology of multidrug resistant K. pneumoniae isolates, obtained from hospitalized patients in Shiraz, Iran.

Methods

In this study, 60 K. pneumoniaeisolates were collected from Nemazee and Faghihi referral hospitals. Antibiotic susceptibility testing and MIC were performed by disk diffusion test and Epsilometer (E)-test strips, respectively. Carbapenemase genes were identified by polymerase chain reaction and sequencing. Then, clonal relationships were analyzed, using PFGE.

Results

Thirty-three out of 60 K. pneumoniae isolates were resistant to carbapenems. Among the isolates, 86.6% were multidrug resistant (MDR). Polymyxin B (18.3%) and tigecycline (23.3%) were shown to be the most active agents against K. pneumoniae isolates. In our study, the high prevalence of bla_NDM (45%) and bla_OXA-48 (10%) was detected.

Conclusion

The results of this study revealed the widespread carbapenemase gene between different wards in hospitals as a risk factor for treatment options. PFGE analysis showed 11 clusters and 3 singletons based on an 80% similarity level. Also, PFGE analysis showed that there were similar genetic patterns among K. pneumoniae isolates and these patterns were responsible for the distribution of infection in hospitals.

Evaluation of Phenotypic and Genotypic Characteristics of Carbapnemases-producing Enterobacteriaceae and Its Prevalence in a Referral Hospital in Tehran City

Background & Objective

Carbapenem-resistant Enterobacteriaceae is a growing concern worldwide including Iran. The emergence of this pathogen is worrying as carbapenem is one of the 'last-line' antibiotics for treatment of infections caused by multi drug resistant gram- negative bacteria. The main objective of this study was to determine the prevalence of carbapenem-resistant Enterobacteriaceae in a referral hospital in Tehran, Iran.

Methods

In this study, all positive isolates of Enterobacteriaceae recorded in blood, urine, and other body fluids were studied during April 2017 to April 2018 in a referral hospital in Tehran. All cases of resistance to carbapenems were first tested by modified Hodge test. All cases with positive or negative test, after gene extraction, were examined genotypically based on the primers designed for the three Klebsiella pneumoniae carbapenemase (KPC), New Delhi metallo-β-lactamase (NDM), and OXA-48 genes by conventional PCR method.

Results

108 isolates (13.6%) were resistant to all cephalosporins as well as to imipenem and meropenem. In a genotypic study, including 45 isolates, 13 isolates were positive for OXA-48 gene, 11 isolates for OXA-48 and NDM genes, 11 isolates for OXA-48, NDM and KPC genes, 4 isolates for OXA-48 genes and KPC, 3 isolates for NDM, one isolate for KPC. On the other hand, two isolates were negative for all three genes examined.

Conclusion

OXA-48 gene was one of the most common genes resistant to carbapenems in Iran. According to studies, the prevalence of antibiotic resistance in Iran is rising dramatically, which reduces the choice of antibiotics to treat severe infections in the future.

Understanding the Epidemiology of Multi-Drug Resistant Gram-Negative Bacilli in the Middle East Using a One Health Approach

In the last decade, extended-spectrum cephalosporin and carbapenem resistant Gram-negative bacilli (GNB) have been extensively reported in the literature as being disseminated in humans but also in animals and the environment. These resistant organisms often cause treatment challenges due to their wide spectrum of antibiotic resistance. With the emergence of colistin resistance in animals and its subsequent detection in humans, the situation has worsened. Several studies reported the transmission of resistant organisms from animals to humans. Studies from the middle east highlight the spread of resistant organisms in hospitals and to a lesser extent in livestock and the environment. In view of the recent socio-economical conflicts that these countries are facing in addition to the constant population mobilization; we attempt in this review to highlight the gaps of the prevalence of resistance, antibiotic consumption reports, infection control measures and other risk factors contributing in particular to the spread of resistance in these countries. In hospitals, carbapenemases producers appear to be dominant. In contrast, extended spectrum beta lactamases (ESBL) and colistin resistance are becoming a serious problem in animals. This is mainly due to the continuous use of colistin in veterinary medicine even though it is now abandoned in the human sphere. In the environment, despite the small number of reports, ESBL and carbapenemases producers were both detected. This highlights the importance of the latter as a bridge between humans and animals in the transmission chain. In this review, we note that in the majority of the Middle Eastern area, little is known about the level of antibiotic consumption especially in the community and animal farms. Furthermore, some countries are currently facing issues with immigrants, poverty and poor living conditions which has been imposed by the civil war crisis. This all greatly facilitates the dissemination of resistance in all environments. In the one health concept, this work re-emphasizes the need to have global intervention measures to avoid dissemination of antibiotic resistance in humans, animals and the environment in Middle Eastern countries.

Detection of bla CTX-M15 and bla OXA-48 genes in Gram-negative isolates from neonatal sepsis in central of Iran

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the prevalence of neonatal sepsis with a focus on antibiotic resistance and the frequency of the bla _CTX-M-15 and bla _OXA-48 genes in Gram-negative isolates.

MATERIALS AND METHODS

A total of 108 Umbilical Cord Blood (UCB) and 153 peripheral blood samples were cultured via BACTEC from May 2017 to June 2018. The bacterial isolates were identified using phenotypic and genotypic analyses. The antibiotic susceptibility profile of the isolates was determined by disk diffusion. PCR was used to determine the frequency of β-lactamase genes.

RESULTS

Among the 153 infants, 21 (13.7%) proved positive for sepsis. Escherichia coli, Staphylococcus epidermidis and Klebsiella pneumoniae were the most frequent isolates in the peripheral blood cultures. E. coli and Stenotrophomonas maltophilia were isolated from two UCB cultures. The highest resistance among the Gram-positive strains was to cefixime, ceftriaxone, cefotaxime and clindamycin. In the Gram-negative bacteria the highest rates of resistance were to ampicillin (91.7%). The frequency of bla _OXA-48 and bla _CTX-M-15 genes was 25% and 50%, respectively.

CONCLUSION

The high antibiotic resistance among the isolates reveals the importance of monitoring antibiotic consumption and improving control standards in the health care system, especially in neonatal wards.

Multi-drug resistant Pseudomonas aeruginosa and Klebsiella pneumoniae circulation in a burn hospital, Tehran, Iran

Pseudomonas aeruginosa and Klebsiella pneumoniae are among the most important Gram-negative bacteria that can cause nosocomial infections, especially in burn patients. It is important to determine genetic relationships in different clinical specimens as well as between clinical and environmental specimens, which can aid in detecting the source of infection.

The aim of this study was to investigate multi-drug resistant Pseudomonas aeruginosa and Klebsiella pneumoniae spread in a burn hospital, Tehran, Iran. After identification, antibiotic susceptibility testing of all isolates was conducted according to the CLSI guidelines. Further, pulsed-field gel electrophoresis (PFGE) was performed for molecular typing.

97 clinical and 33 environmental specimens were collected. 40 (55%) clinical strains of P. aeruginosa and K. pneumoniae were highly drug resistant. PFGE findings showed similar genetic features to those seen in multi-drug resistant and/or extensively drug resistant P. aeruginosa and K. pneumoniae in clinical and environmental isolates. Inhibition of bacterial spread in the hospital can help to control health care-associated infection and subsequently decrease the morbidity and mortality in hospitalized patients, particularly immunocompromised populations such as burn patients.

Molecular Epidemiology and Drug Resistance Pattern of Carbapenem-Resistant Klebsiella pneumoniae Isolates from Iran

The emergence and dissemination of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates and their involvement in several nosocomial outbreaks are of high concern. This study was conducted to investigate the genetic relatedness and molecular determinants of carbapenem resistance in 100 CRKP isolates. Susceptibility to carbapenems as well as other antibiotics was determined by using disk diffusion method. The Modified Hodge test was performed for detection of carbapenemase production. The minimum inhibitory concentrations of selected antibiotics were determined by broth microdilution method. The presence of bla_OXA-48, bla_KPC, bla_NDM, and bla_VIM carbapenemase genes was examined by PCR, and clonal relatedness of CRKP isolates was investigated by pulsed-field gel electrophoresis (PFGE) analysis. bla_OXA-48 was the most frequent carbapenemase gene (72%), followed by bla_NDM (31%). None of the isolates harbored bla_KPC and bla_VIM genes. PFGE separated the majority of isolates into 10 clusters, including the major clusters A and B, carrying bla_OXA-48, and clusters C and D, carrying bla_NDM, and 4 isolates had a unique PFGE pattern. An increased rate of colistin resistance (50%) was detected among the isolates. Tigecycline was found to be the most active agent against CRKP isolates. Our results revealed that high prevalence of bla_OXA-48 and bla_NDM carbapenamses and resistance to colistin are alarming threats, necessitating an immediate action to prevent the spread of carbapenem-colistin-resistant K. pneumoniae isolates in Iran.

The threat of carbapenem-resistant gram-negative bacteria in a Middle East region

Data on the status of carbapenem-resistant microorganisms in the Middle East countries are scarce. The aim of this review was to collect available data regarding resistance to carbapenems in a Middle East region. Available data regarding carbapenem-resistant isolates were considered for evaluation in this review. Biomedical electronic databases were systematically searched to find related articles. The key terms used were "carbapenem-resistant, resistant gram-negative bacilli, Enterobacteriaceae, fermenting and non-fermenting gram-negative bacilli, Pseudomonas, Acinetobacter, Klebsiella and Iran". After primary screening, 275 relevant articles were selected to be assessed thoroughly. Resistance rate to carbapenems was reported between 1% and 86% during years 2006-2018. Most of the carbapenem-resistant microorganisms were isolated from burn patients. Modified Hodge test was a commonly used phenotypic test. Only in few studies, genotypic assays were considered. Pattern of antibiotic use can affect emergence of resistant microorganisms. Rational use of drugs, and specifically, antibiotics is a challenging issue in developing countries. Mean number of drugs per prescription in these countries was higher than the World Health Organization standards. Overuse of antibiotics, especially injectable ones, and easy access to antibiotics without prescription is a warning alarm for future antibiotic resistance in developing countries. Establishing antimicrobial stewardship's programs is new in the hospitals. Unfortunately, rules and regulatory issues to restrict antibiotic access in community pharmacies and prescription by general physicians are limited.

Emergence of co-existence of blaNDM with rmtC and qnrB genes in clinical carbapenem-resistant Klebsiella pneumoniae isolates in burning center from southeast of Iran

Dissemination of carbapenemase-producing Klebsiella pneumoniae along with 16S rRNA methyltransferase (16S-RMTase) has been caused as a great concern for healthcare settings. The aim of this study was to investigate the prevalence of resistance genes among K. pneumoniae isolates. During October 2015 to February 2016, 30 non-duplicative K. pneumoniae strains were isolated from clinical specimens in a burn center in Kerman, Iran. Antibiotic susceptibility tests of isolates, carbapenemase, extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamase-producing isolates were determined by phenotypic methods. The beta-lactamase, oqxA/B efflux pumps, qnr A, B, S, 16S-RMTase (rmt A, B, and C), and mcr-1 resistance genes were determined by PCR. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was used for molecular typing. According to our findings, tigecycline has been shown the most active agent against K. pneumoniae isolates. Antibiotic resistance genes, bla_TEM-1, bla_SHV-12, bla_CTX-M-15, bla_CTX-M-2, bla_NDM-1, bla_FOX, bla_MOX, bla_EBC, bla_ACC, bla_CIT, rmtC, qnrB, qnrS, oqxA, and oqxB, were detected in 11 (36.7%), 13 (43.3%), 11 (36.6%), 5 (16.6%), 9 (30%), 1 (3.3%), 1 (3.3%), 1 (3.3%), 1 (3.3%), 2 (6.7%), 1 (3.3%), 9 (30%), 2 (6.7%), 18 (60%), and 13 (43.3%) of isolates, respectively. The bla_NDM-1 with rmtC was simultaneously observed in one isolate. ERIC-PCR results revealed 25 distinct patterns in eight clusters (A-H) and five singletons. This study highlights the high prevalence of bla_NDM and emergence of rmtC among carbapenem-resistant K. pneumoniae. The resistance genes are often co-located on the conjugative plasmids, so it might be the reason of the rapid spread of them. The prevalence of multidrug-resistant K. pneumoniae isolates limits the available treatment options and presents tremendous challenges to public health.

EXTENDED-SPECTRUM BETA-LACTAMASE PRODUCING GRAM NEGATIVE BACTERIA IN IRAN: A REVIEW

Background:

The emergence and spread of extended spectrum β-lactamase (ESBL)-producing Gram- negative bacteria (GNB), particularly in Enterobacteriaceae, Acinetobacter baumannii, and Pseudomonas aeruginosa, have increased all over the world. ESBLs are characterized by their ability to hydrolyze β-lactams, early cephalosporins, oxyimino-thiazolyl cephalosporins, and monobactams, but not cephamycins or carbapenems. The rate of nosocomial infections caused by ESBL-producing GNB in Asia Pacific has increased and several studies have identified their prevalence in the region. The aim of this study is to review the prevalence of ESBL-producing GNB in the West Asia and the Middle East with a particular focus on Iran.

Materials and Methods:

The available evidence from various studies (Microbia and clinical studies, retrieved from the PubMed, and Scopus databases) regarding the ESBL producing Gram negative bacteria in Iran were evaluated.

Results:

In almost all parts of the country, high resistance has been observed, especially in the central part of Iran. Up to 89.8% Escherichia coli, 72.1% Klebsiella pneumonia, 84.2% Acinetobacter baumannii, and 83.8% Pseudomonas aeruginosa isolates are ESBL positive.

Conclusion:

The present study showed the increasing prevalence of ESBLs in different regions of Iran, which could be useful to strategic policy towards reducing reduce their prevalence.

Global Dissemination of Carbapenemase-Producing Klebsiella pneumoniae: Epidemiology, Genetic Context, Treatment Options, and Detection Methods

The emergence of carbapenem-resistant Gram-negative pathogens poses a serious threat to public health worldwide. In particular, the increasing prevalence of carbapenem-resistant Klebsiella pneumoniae is a major source of concern. K. pneumoniae carbapenemases (KPCs) and carbapenemases of the oxacillinase-48 (OXA-48) type have been reported worldwide. New Delhi metallo-β-lactamase (NDM) carbapenemases were originally identified in Sweden in 2008 and have spread worldwide rapidly. In this review, we summarize the epidemiology of K. pneumoniae producing three carbapenemases (KPCs, NDMs, and OXA-48-like). Although the prevalence of each resistant strain varies geographically, K. pneumoniae producing KPCs, NDMs, and OXA-48-like carbapenemases have become rapidly disseminated. In addition, we used recently published molecular and genetic studies to analyze the mechanisms by which these three carbapenemases, and major K. pneumoniae clones, such as ST258 and ST11, have become globally prevalent. Because carbapenemase-producing K. pneumoniae are often resistant to most β-lactam antibiotics and many other non-β-lactam molecules, the therapeutic options available to treat infection with these strains are limited to colistin, polymyxin B, fosfomycin, tigecycline, and selected aminoglycosides. Although, combination therapy has been recommended for the treatment of severe carbapenemase-producing K. pneumoniae infections, the clinical evidence for this strategy is currently limited, and more accurate randomized controlled trials will be required to establish the most effective treatment regimen. Moreover, because rapid and accurate identification of the carbapenemase type found in K. pneumoniae may be difficult to achieve through phenotypic antibiotic susceptibility tests, novel molecular detection techniques are currently being developed.

Dissemination of carbapenemases producing Gram negative bacteria in the Middle East

The emergence and spread of carbapenemase-producing bacteria, that hydolyze most β-lactams, including carbapenems, are a major concern of public health system worldwide, particularly in the Middle East area. Since the plasmids harboring resistance genes could be spread across other bacterial populations, detection of carbapenemase-producing organisms has become more problematic. These organisms produce different types of enzymes including the most prevalent types including KPC, VIM, IMP, NDM, and OXA-48. Carbapenemase producers are mostly identified among Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. This study reviewed almost all papers, which conducted in the Middle East. In order to decrease the spread of resistance, the regional cooperation has been emphasized by the Middle East countries. The highest resistance, which is mediated by KPC has been observed in Afghanistan, Saudi Arabia and Jordan followed by NDM in Pakistan and OXA in Turkey and Pakistan. It is important to mention that the spread of these types have been reported sporadically in the other countries of this area. This review described the widespread carbapenemases in the Middle East area, which have been identified in an alarming rate.

Characterization of Carbapenemases in Extensively Drug Resistance Acinetobacter baumannii in a Burn Care Center in Iran

The emergence of multidrug resistance (MDR) and extensively drug resistance (XDR) in Acinetobacter baumannii has made an important challenge in the treatment of infections caused by this organism. The ability of carbapenemase production is one of the main mechanisms for the emergence of MDR and/or XDR in A. baumannii. The aim of this study was to detect carbapenemase producer A. baumannii. In this study, 65 imipenem resistant A. baumannii were collected from burned patients. Biochemical identification, antibiotic susceptibility test and multiplex polymerase chain reactions for the detection of carbapenemases genes were performed. The results showed that all strains carried bla OXA-51. 83%, 12.5% and 9.23% strains harbored bla OXA-23, bla VIM and bla KPC genes, respectively. None of the isolates carried bla IMP, bla OXA-48, blaNDM-1 and bla SPM-1 genes. The results of this study indicate the emergence of Klebsiella pneumoniae Carbapenemase (KPC) in A. baumannii causing nosocomial infections in burned patients which can be important for hospital infection prevention systems in Iran.