Prevalence, antibiotic susceptibility and characterization of antibiotic resistant genes among carbapenem-resistant Gram-negative bacilli and yeast in intestinal flora of cancer patients in North Lebanon

Fungus reduces tetracycline-resistant genes in manure treatment by predation of bacteria

New strategies to remove antibiotic resistance genes (ARGs), one of the most pressing threats to public health, are urgently needed. This study showed that the fungus Phanerochaete chrysosporium seeded to a composting reactor (CR) could remarkably reduce tetracycline-resistant genes (TRGs). The reduction efficiencies for the five main TRGs (i.e., tetW, tetO, tetM, tetPA, and tet(32)) increased by 8 to 100 folds compared with the control without P. chrysosporium, and this could be attributed to the decrease in the quantity of bacteria. Enumeration based on green fluorescence protein labeling further showed that P. chrysosporium became dominant in the CR. Meanwhile, the bacteria in the CR invaded the fungal cells via the cell wall defect of chlamydospore or active invasion. Most of the invasive bacteria trapped inside the fungus could not survive, resulting in bacterial death and the degradation of their TRGs by the fungal nucleases. As such, the predation of tetracycline-resistant bacteria by P. chrysosporium was mainly responsible for the enhanced removal of TRGs in the swine manure treatment. This study offers new insights into the microbial control of ARGs.

The role of gut microbiota and metabolites in cancer chemotherapy

BACKGROUND

The microbiota inhabits the epithelial surfaces of hosts, which influences physiological functions from helping digest food and acquiring nutrition to regulate metabolism and shaping host immunity. With the deep insight into the microbiota, an increasing amount of research reveals that it is also involved in the initiation and progression of cancer. Intriguingly, gut microbiota can mediate the biotransformation of drugs, thereby altering their bioavailability, bioactivity, or toxicity.

AIM OF REVIEW

The review aims to elaborate on the role of gut microbiota and microbial metabolites in the efficacy and adverse effects of chemotherapeutics. Furthermore, we discuss the clinical potential of various ways to harness gut microbiota for cancer chemotherapy.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Recent evidence shows that gut microbiota modulates the efficacy and toxicity of chemotherapy agents, leading to diverse host responses to chemotherapy. Thereinto, targeting the microbiota to improve efficacy and diminish the toxicity of chemotherapeutic drugs may be a promising strategy in tumor treatment.

Fecal Carriage of Extended-Spectrum β-Lactamase and Carbapenemase-Producing Enterobacteriaceae Among Oncology and Non-Oncology Patients at Jimma Medical Center in Ethiopia: A Comparative Cross-Sectional Study

Purpose

Extended-spectrum β-lactamase (ESBL) and carbapenemase-producing Enterobacteriaceae (CPE) are among the major threats to global health because of their encoded protection against key antibiotics.

Methods

A comparative cross-sectional study was conducted among oncology and non-oncology patient groups (1:1; n = 214) on a consecutive sampling approach. Stool or rectal swab was collected from June 2021 to November 2021 and screened for ESBL-PE and CPE using ChromID-ESBL media. Confirmation for the enzymes was made by using combination disc and modified carbapenem inactivation methods, respectively. Disk diffusion method was used to determine antimicrobial susceptibility testing following the recommendations of CLSI 2022. SPSS software version 23 was used for data analysis.

Results

Fecal carriage prevalence of ESBL-PE was found in 90 (84.1%) of oncology participants and in 77 (71.9%) of non-oncology patients (p = 0.032). Escherichia coli was the most common ESBL-PE isolate in 82 (62.5%) and 68 (88.3%) of oncology and non-oncology patients, followed by Klebsiella oxytoca [15 (11.5%) versus 6 (7.8%)], respectively. Out of the total ESBL-PE isolates from both oncology and non-oncology patient groups, the maximum level of resistance was observed against ciprofloxacin 177 (86.3%), trimethoprim-sulfamethoxazole 103 (80.3%), tetracycline 97 (75.8%), whereas enhanced susceptibility was appreciated to tigecycline 200 (97.6%), meropenem 162 (79.0%), and ertapenem 145 (70.7%) with no significant difference between oncology and non-oncology group. Carbapenemase-producing isolates from oncology patients were 12 (11.2%), whereas it was 4 (3.7%) (p = 0.611) from non-oncology group. Bacterial isolates from oncology in this study showed a trend of multiple drug resistance of 113 (88.3%).

Conclusion

The results revealed alarmingly high carriage rates of ESBL and CPE among all study participants. Moreover, the isolates showed increased resistance rates to alternative drugs and had multiple antibiotic-resistant patterns. Hence, it is important to emphasize strict adherence to antimicrobial stewardship program as well as infection prevention and control practices.

Antifungal Use and Resistance in a Lower-Middle-Income Country: The Case of Lebanon

Antimicrobial resistance is a serious threat, particularly in low- and middle-income countries (LMICs). Antifungal resistance is often underestimated in both healthcare and non-clinical settings. In LMICs, it is believed that the inappropriate use of antifungals, limited surveillance systems, and low diagnostic capacities are significant drivers of resistance. Like other LMICs, Lebanon lacks antifungal use and resistance surveillance programs, and the impact of antifungal resistance in the country remains unclear, especially during the unfolding economic crisis that has severely affected medical care and access to safe food and water. Interestingly, the widespread use of antifungals in medicine and agriculture has raised concerns about the development of antifungal resistance in Lebanon. In this light, we aimed to survey available antifungal drugs in the country and evaluate susceptibility patterns of prevalent fungal species to guide empiric treatments and develop antifungal stewardship programs in Lebanon. We noted that the economic crisis resulted in significant increases in antifungal drug prices. Additionally, a comprehensive literature search across PubMed, ScienceDirect, and Google Scholar databases identified 15 studies on fungal infections and antifungal resistance conducted from 1998 to 2023 in Lebanon. While data on antifungal resistance are limited, 87% of available studies in Lebanon focused on candidiasis, while the remaining 13% were on aspergillosis. Overall, we observed a marked antimicrobial resistance among Candida and Aspergillus species. Additionally, incidences of Candida auris infections have increased in Lebanese hospitals during the COVID-19 pandemic, with a uniform resistance to fluconazole and amphotericin-B. Taken together, a One Health approach, reliable diagnostics, and prudent antifungal use are required to control the spread of resistant fungal pathogens in healthcare and agricultural settings.

Updates on the Status of Carbapenem-Resistant Enterobacterales in Lebanon

Carbapenem-resistant Enterobacterales (CRE) pathogens have been increasingly isolated and reported in Lebanon. Several studies have been published over the last two decades about the CRE situation in the country. However, compared to the worldwide data, those studies are scarce and mostly restricted to single center studies. In this review, we aim to present a comprehensive and reliable report illustrating the current situation regarding CRE in Lebanon. Variable studies have shown an increasing pattern of carbapenem resistance in Enterobacterales since the first reports of CRE isolates in 2007 and 2008. Escherichia coli and Klebsiella pneumoniae were the most detected ones. The OXA-48 class D carbapenemases were the most prevalent carbapenemases among CRE isolates. Moreover, the emergence of other carbapenemases like the NDM class B carbapenemase has been noticed. Strict infection control measures in hospitals, including the identification of CRE carriers, are needed in Lebanese hospitals since carriage is a potential risk for the spread of CRE in healthcare settings. The dissemination of CRE in the community is noticed and attributed to multiple causes, such as the refugee crisis, water contamination, and antimicrobial misuse. In conclusion, strict infection control measures in healthcare settings, in addition to accurate antimicrobial stewardship program implementation, are urgently needed.

Extended-Spectrum β-Lactamases (ESBL) Producing Bacteria in Animals

Animals have been identified as potential reservoirs and vectors of resistance genes, with studies showing that Gram-negative bacteria can acquire resistance through the horizontal transmission of resistance genes on plasmids. It is important to understand the distribution of antimicrobial-resistant bacteria and their drug-resistant genes in animals. Previous review articles mostly focused on a single bacterium or a single animal. Our objective is to compile all ESBL-producing bacteria isolated from various animals in recent years and provide a comprehensive viewpoint. Using a thorough PubMed literature search spanning from 1 January 2020 to 30 June 2022, studies exploring extended-spectrum beta-lactamase (ESBL) producing bacteria in animals were included. ESBL-producing bacteria are present in animals from various countries around the world. The most common sources of these bacteria were farm animals, and the most frequently isolated bacteria were Escherichia coli and Klebsiella pneumoniae. The most detected ESBL genes were blaTEM, blaSHV, and blaCTX-M. The presence of ESBL-producing bacteria in animals highlights the importance of the One Health approach to address the issue of antibiotic resistance. Further research is needed to better understand the epidemiology and mechanisms of the spread of ESBL-producing bacteria in animal populations and their potential impact on human and animal health.

First Report of Extended-Spectrum β-Lactamase (blaCTX-M1) and Colistin Resistance Gene mcr-1 in E. coli of Lineage ST648 from Cockroaches in Tunisia

The emergence of multidrug-resistant bacteria has become a major problem. Cockroaches may play an important role in the spread of those bacteria between the environment and humans. This study was designed to screen extended-spectrum β-lactamase (ESBL)-producing and colistin-resistant strains and to investigate the molecular support of multidrug-resistant Enterobacteriaceae in the external surface and gut homogenates of cockroaches collected from different locations in Tunisia. Between July 2017 and June 2018, 144 Enterobacteriaceae samples were isolated from 115 trapped cockroaches (collective catering, houses, and a hospital). Antibiotic susceptibility testing was performed using the disk diffusion method. Extended-spectrum β-lactamase-encoding genes and the mcr-1 gene were investigated by real-time PCR (RT-PCR) and standard PCR. The genetic relationship among isolates was studied with the help of multilocus sequence type (MLST) analysis. Of the 144 Enterobacteriaceae isolates, 22 strains exhibited a positive ESBL-screening test (73.3%), including 17 Escherichia coli isolates and 5 Klebsiella pneumoniae isolates. Among them, 9 Escherichia coli isolates were resistant to colistin, with an MIC ranging from 8 to16 μg/L, all of which harbored the mcr-1 gene. Eight bla_CTX-M-15 genes were detected; two among them were associated with bla_TEM-117 and bla_TEM-128, and seven bla_CTX-M-1 genes were detected that also harbored the mcr-1 gene. Genotyping analysis revealed 7 different sequence types already described in humans and animals. We report the first survey of mcr-1 in ESBL-producing E. coli isolates from cockroaches. Our findings highlight cockroaches as a source of nosocomial infections, and they are a reservoir of colistin-resistant E. coli, which is a carrier of other additional risk genes such as bla_ESBL, especially in hospitals.

IMPORTANCE Multidrug resistance in Enterobacteriaceae has become a major concern worldwide that is increasingly observed in human, animals, and also cockroaches. In our study, we found that cockroaches may play an important role as a potential vector of multidrug-resistant Enterobacteriaceae in the hospital environment and collective catering. Our study describes the first survey of mcr-1 in ESBL-producing E. coli isolates from hospital cockroaches. Our results further highlight the possibility that mcr-1 may enter humans via cockroach contamination and thereby threaten public health. Our results show that these cockroaches are an important reservoir of colistin-resistant E. coli and carriers of other additional risk genes such as bla_ESBL, hence the importance of strengthening prevention strategies and of strictly respecting hygiene measures in order to control their distribution and spread in Tunisia.

Clonal Dissemination of Plasmid-Mediated Carbapenem and Colistin Resistance in Refugees Living in Overcrowded Camps in North Lebanon

Carbapenem and colistin-resistant bacteria represent a global public health problem. Refugees carrying these bacteria and living in inadequate shelters can spread these microorganisms. The aim of this study was to investigate the intestinal carriage of these bacteria in Syrian refugees in Lebanon. Between June and July 2019, 250 rectal swabs were collected from two refugee camps in North Lebanon. Swabs were cultured on different selective media. Antibiotic susceptibility testing was performed using the disk diffusion method. Carbapenemase-encoding genes and mcr genes were investigated using real-time polymerase chain reaction (RT-PCR) and standard polymerase chain reaction (PCR). Epidemiological relatedness was studied using multilocus sequence typing (MLST). From 250 rectal swabs, 16 carbapenem-resistant, 5 colistin-resistant, and 4 colistin and carbapenem-resistant Enterobacteriaceae were isolated. The isolates exhibited multidrug-resistant phenotypes. Seven Klebsiella pneumoniae isolates harboured the bla_OXA-48 gene, and in addition four K. pneumoniae had mutations in the two component systems pmrA/pmrB, phoP/phoQ and co-harboured the bla_NDM-1 gene. Moreover, the bla_NDM-1 gene was detected in six Escherichia coli and three Enterobacter cloacae isolates. The remaining five E. coli isolates harboured the mcr-1 gene. MLST results showed several sequence types, with a remarkable clonal dissemination. An urgent strategy needs to be adopted in order to avoid the spread of such resistance in highly crowded underserved communities.

Phenotypic and genotypic characterisation of cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacterial pathogens in Lebanon, Jordan and Iraq

Antimicrobial resistance (AMR) is a worldwide health concern that continues to escalate. A PubMed literature search identified articles from January 2015-August 2020 reviewing cephalosporin-, carbapenem- and colistin-resistant Gram-negative bacteria (GNB) in Lebanon, Jordan and Iraq, specifically focused on three main pathogens, namely Acinetobacter spp., Enterobacteriaceae (i.e. Escherichia coli and Klebsiella spp.) and Pseudomonas aeruginosa. Sixty-seven relevant articles published within the past 5 years highlighting trends in AMR in Lebanon, Jordan and Iraq were included. Increased resistance to carbapenems in Acinetobacter spp. isolates was observed in Lebanon, Jordan and Iraq; colistin resistance remained relatively low. Studies on Enterobacteriaceae isolates were more varied, with high rates of carbapenem and cephalosporin resistance and lower levels of colistin resistance in Lebanon. Studies from Iraq found high cephalosporin and colistin resistance along with increased susceptibility to carbapenems. In Jordan, most studies recorded high resistance to cephalosporins along with high susceptibility to carbapenems and colistin. Studies on P. aeruginosa isolates were limited: most isolates in Lebanon were carbapenem-resistant and colistin-susceptible; studies in Iraq showed varying levels of resistance to carbapenems and cephalosporins with high susceptibility to colistin; and studies in Jordan found varying levels of susceptibility to carbapenems, cephalosporins and colistin. The most commonly observed resistance mechanisms in GNB were genetic modifications causing increased expression of antimicrobial-inactivating enzymes and decreased permeability. Overall, this review highlights the concerning rise in AMR and the need for improved understanding of the resistance mechanisms to better inform healthcare providers when recommending treatment for patients in this region.

Prevalence and molecular epidemiology of carbapenem-resistant Gram-negative bacilli and their resistance determinants in the Eastern Mediterranean Region over the last decade

Carbapenem resistance in Enterobacteriaceae, Acinetobacter baumannii and Pseudomonas aeruginosa is increasing worldwide, which has led the World Health Organization (WHO) to list these bacteria in the critical priority pathogens group. Infections by such pathogens pose a serious threat to hospitalised patients and are associated with clinical and economic consequences. What worsens the case is the weak pipeline of available antimicrobial agents to treat such infections and the absence of new drugs. The aim of this review was to shed light on all studies tackling carbapenem resistance in Enterobacteriaceae, A. baumannii and P. aeruginosa in the Eastern Mediterranean region, with indication for each country, description of studies timeline, prevalence of carbapenem resistance, and carbapenem resistance-encoding genes detected in these countries.

The Impact of Modifying Empirical Antibiotic Therapy Based on Intestinal Colonization Status on Clinical Outcomes of Febrile Neutropenic Patients

Background

This paper aimed to inspect factors affecting febrile neutropenia patients with hematologic malignancies. The intestinal colonization rate of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenem-resistant Enterobacteriaceae (CRE) was assessed. The rate of subsequent ESBL-E and CRE bacteremia correlated with corresponding bacterial colonization was evaluated. Further, the risk factors for ESBL-E and CRE intestinal colonization were examined. Finally, the impact of rectal swab screening combined with adapted empirical antibiotic therapy on the mortality rate of patients with febrile neutropenia was assessed.

Materials and Methods

Febrile neutropenia patients underwent rectal swabs and collection of blood culture specimens upon admission. Empirical treatment was subsequently modified according to rectal swab results if necessary. Bacteremia patients were treated according to blood culture results. Explorative forward-stepwise logistic regression analyses were used to identify risk factors for ESBL-E and CRE fecal carriage and mortality.

Results

In total, 201 rectal swabs and 402 blood samples were collected from 163 patients during 201 febrile neutropenia episodes. Of these episodes, 38 (18.90%) were colonized with ESBL-E and 30 (14.92%) with CRE. Bloodstream infections developed in 29/201 (14.42%) episodes. Only bacteremia episodes caused by Gram-negative bacilli were included in our analysis. The development of Gram-negative-rod bacteremia was observed in eight out of 38 (21.05%) ESBL-E colonized episodes and four out of 30 (13.33%) CRE-colonized episodes. A BSI developed in three out of 38 (7.89%) ESBL-E colonized episodes, and two out of 30 (6.66%) CRE-colonized episodes developed BSI with the respective organism. Multivariate analysis identified previous quinolone use as the only independent risk factor for fecal colonization of multi-drug-resistant (MDR) Enterobacteriaceae (ESBL-E and CRE) (odds ratio, 17.09; 95% confidence interval, 5.29 - 55.18; P <0.0001). No significant association was observed between ESBL-E and CRE carriage and increased risk of developing subsequent bacteremia. No significant differences were detected between groups receiving modified and non-modified treatments in duration of hospitalization or antibiotic therapy (univariate analysis) and 28-day mortality rate (logistic regression).

Conclusion

Quinolone exposure was a major risk factor for ESBL-E and CRE fecal carriage. Performing rectal swab screening for MDR Enterobacteriaceae and modifying empirical antibiotic therapy accordingly did not improve clinical outcomes of febrile neutropenia patients.

Species distribution and antifungal susceptibility of Aspergillus clinical isolates in Lebanon

Aim: We sought to provide first insights into the epidemiology and antifungal susceptibility patterns of the aspergilli in Lebanon. Materials & methods: After species identification, antifungal susceptibility was investigated according to EUCAST recommendations. CYP51A gene was sequenced in resistant isolates and its expression level was evaluated by Reverse transcription-quantitative PCR. Results: Among the 73 Aspergillus isolates studied (mostly from ears), the predominant species was Aspergillus niger (54.8%). The overall drug resistance was highest for amphotericin B (38.4%), followed by itraconazole (31.5%), posaconazole (30.1%) and voriconazole (23.3%). In addition, CYP51A gene mutations were not the major cause of azole resistance among these isolates. Conclusion: Our findings indicate the paramount need for an integral One Health strategy and a national reference center for invasive mycoses and antifungals.

Emerging superbugs: The threat of Carbapenem Resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) are gram-negative bacteria that are resistant to carbapenems, a group of antibiotics considered as the last-resource for the treatment of infections caused by multidrug-resistant bacteria. CRE constitutes a major threat to health care systems because infections caused by these pathogens are difficult to treat and are commonly associated with high mortality due to the limited availability of effective antibiotics. While infection prevention and timely detection are of vital importance to control CRE infections, developing new and effective anti-CRE therapies is also crucial. Accumulating evidence indicates that gut microbiota alteration (dysbiosis) is associated with an increased intestinal colonization with CRE and consequently with higher risk of developing CRE infections. Importantly, therapeutic interventions aimed to modify the gut microbiota composition via fecal microbiota transplantation (FMT) have been explored in various clinical settings with some of them showing promising results, although larger clinical trials are needed to confirm the efficacy of this strategy. Here, we highlight the challenges associated with the emergence of CRE infections.

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.

Emergence of plasmid-encoded VIM-2-producing Pseudomonas aeruginosa isolated from clinical samples in Lebanon

The present study aimed to describe the emergence of carbapenem-resistant Pseudomonas aeruginosa isolated from clinical Lebanese patients. The resistance of these isolates is due to the presence of the plasmid-encoded bla_VIM-2 gene. We provide its first description in Lebanon, as well as a description of disruption of the oprD gene by mutations.

The pollution level of the blaOXA-58 carbapenemase gene in coastal water and its host bacteria characteristics

This paper investigated 10 carbapenemase genes and selected the hosts of these genes in the estuary of Bohai Bay. The results showed that the OXA-58 producer accounted for a large percentage of carbapenem resistant bacteria in the sampling points, whereas the VIM, KPC, NDM, IMP, GES, OXA-23, OXA-24, OXA-48 and OXA-51 producers were not detected in the study. In addition, 9 bacterial genera with 100% identical bla_OXA-58 sequences, including Pseudomonas, Rheinheimera, Stenotrophomonas, Shewanella, Raoultella, Vibrio, Pseudoalteromonas, Algoriphagus, Bowmanella and Thalassospira, were isolated from seawater. It is suggested that the host of bla_OXA-58 gene were varied and many kinds of them could survive in the seawater. Moreover, we preformed the quantitative RT-PCR and the result shown the abundance of bla_OXA-58 fluctuated between 2.8×10^-6 copies/16S and 2.46×10^-4 copies/16S, which was of the same order of magnitude as some common antibiotic resistance genes in environment. Furthermore, the variation trend of bla_OXA-58 gene suggested that pollution discharge and horizontal gene transfer could contribute to the increase of the gene in coastal area.

Risk factors for carbapenem-resistant Enterobacteriaceae infections: a French case-control-control study

This study aimed to assess characteristics associated with infections due to carbapenem-resistant Enterobacteriaceae (CRE), producing (CPE) or not producing (non-CPE) carbapenemase, among hospitalised patients in 2014-2016 in France. Case-patients with CRE were compared to two control populations. In multivariate analysis comparing 160 CRE cases to 160 controls C1 (patients with a clinical sample positive for carbapenem-susceptible Enterobacteriaceae), five characteristics were linked to CRE: male gender (OR = 1.9; 95% CI = 1.3-3.4), travel in Asia (OR = 10.0; 95% CI = 1.1-91.2) and hospitalisation in (OR = 2.4; 95% CI = 1.3-4.4) or out of (OR = 4.4; 95% CI = 0.8-24.1) France in the preceding 12 months, infection in the preceding 3 months (OR = 3.0; 95% CI = 1.5-5.9), and antibiotic receipt between admission and inclusion (OR = 1.9; 95% CI = 1.0-3.3). In multivariate analysis comparing 148 CRE cases to 148 controls C2 [patients with culture-negative sample(s)], four characteristics were identified: prior infection (OR = 3.3; 95% CI = 1.6-6.8), urine drainage (OR = 3.0; 95% CI = 1.5-6.1) and mechanical ventilation (OR = 3.7; 95% CI = 1.1-13.0) during the current hospitalisation, and antibiotic receipt between admission and inclusion (OR = 6.6; 95% CI = 2.8-15.5). Univariate analyses comparing separately CPE cases to controls (39 CPE vs C1 and 36 CPE vs C2) and non-CPE cases to controls (121 non-CPE vs C1 and 112 non-CPE vs C2), concomitantly with comparison of CPE to non-CPE cases showed that only CPE cases were at risk of previous travel and hospitalisation abroad. This study shows that, among CRE, risk factors are different for CPE and non-CPE infection, and suggests that question patients about their medical history and lifestyle should help for early identification of patients at risk of CPE among patients with CRE.

Antibiotic resistance and molecular characterization of diarrheagenic Escherichia coli and non-typhoidal Salmonella strains isolated from infections in Southwest China

BACKGROUND

Bacterial diarrhea is one of the most common causes for medical consultations, mortality and morbidity in the world. Diarrheagenic Escherichia coli (DEC) and non-typhoidal Salmonella (NTS) are major intestinal pathogens in developing countries, and the indiscriminate use of antibiotics has greatly contributed to resistant strains. Hence, the aim of the present study is to identify the antimicrobial resistance patterns and the molecular characteristics of DEC and NTS in southwest, China.

METHODS

1121 diarrheal patients and 319 non-diarrheal subjects across all age groups were recruited from four sentinel hospitals from June 2014 to July 2015 in Kunming City, Yunnan Province. Each stool specimen was collected to detect DEC and NTS with standard microbiological and molecular methods. Antimicrobial resistance testing was performed with the Kirby-Bauer disk diffusion method, and the standards for antimicrobial susceptibility testing complied with the Clinical and Laboratory Standards Institute (CLSI). Molecular characterization of strains was carried out using pulsed-field gel electrophoresis (PFGE). A structured questionnaire was used to record basic epidemiological data (e.g. sex, age, residence, season, etc.). Data were analyzed using Chi-square or Fisher's exact test.

RESULTS

DEC was detected in 127 (11.33%) diarrhea cases and 9 (2.82%) non-diarrheal cases (χ² = 20.69, P < 0.001, OR = 4.36, 95% CI: 2.19-8.65), and the prevalence of NTS isolated from diarrhea cases was higher than that of non-diarrheal cases across all age groups (n = 42, 3.75%, n = 1, 0.31%, χ² = 10.10, P = 0.002, OR = 12.38, 95% CI: 1.70-90.29). The rates of resistance to ten antibiotics of DEC and NTS showed significant differences (χ ²  = 386.77, P < 0.001; χ² = 191.16, P < 0.001). The rates of resistance to Amoxicillin and Clavulafiate (AMC), Cephalothin (CEP), Gentamicin (GEN) and Sulfamethoxazole-Trimethoprim (SXT) of DEC isolated from diarrhea cases were higher than those of NTS isolated from diarrhea patients (37.01% vs 14.29%, χ² = 7.57, P = 0.006; 29.92% vs 11.90%, χ² = 5.40, P = 0.02; 37.01% vs 11.90%, χ² = 5.80, P = 0.016; 62.20% vs 26.19%, χ² = 16.44, P < 0.001; respectively). Ciprofloxacin (CIP) was the most sensitive antibiotic for DEC and NTS strains isolated from diarrhea cases. Resistance rates of DEC isolates from cases and controls to more than three kinds antimicrobials (multidrug resistance, MDR) showed no significant differences (81.10% vs 88.89%, P = 0.33). Pulsotype patterns of DEC strains were highly diverse; however, the pulsotype pattern of NTS strains was closely related to the serotype. The pattern of S. enteritidis was highly similar, but the S. enterica Typhimurium strain was discrete.

CONCLUSIONS

Antibiotic resistance of Enterobacteriaceae is of great concern. The societal effects of antibiotic use justify strict monitoring to combat increases in antimicrobial resistance. Molecular epidemiology and systematic epidemiological investigation can provide accurate evidence for tracking the infection source.

OXA-48-like carbapenemases producing Enterobacteriaceae in different niches

The emergence of carbapenem-resistant enterobacterial species poses a serious threat to public health worldwide. OXA-48-type carbapenem-hydrolyzing class D β-lactamases are widely distributed among Enterobacteriaceae, with significant geographical differences. To date, 11 OXA-48-like variants have been identified, with classical OXA-48 being the most widespread. These enzymes show high-level hydrolytic activity against penicillins and low-level hydrolysis towards carbapenems. Since the first description of the OXA-48 carbapenemase in Turkey, bacterial strains producing the enzyme have been extensively reported in nosocomial and community outbreaks in many parts of the word, particularly in the Mediterranean area and European countries. The rapid spread of Enterobacteriaceae producing OXA-48-like enzymes in different ecosystems has become a serious issue recently. The number of reservoirs for such organisms is increasing, not only in hospitals, but also in the community, among animals (e.g., livestock, companion animals, and wildlife) and in the environment. This review aims to summarize the main characteristics of the OXA-48-type carbapenemases, covering genetic and enzymatic traits, their epidemiology, clonality and associated genes, correlation with extended-spectrum β-lactamases (ESBLs) or plasmidic AmpC (pAmpC) in different bacterial species worldwide.