The carbapenem-resistant Enterobacteriaceae threat is growing: NDM-1 epidemic at a training hospital in Turkey

Prevalence and factors associated with carbapenem-resistant Enterobacterales (CRE) infection among hematological malignancies patients with CRE intestinal colonization

BACKGROUND

Knowledge about the prevalence, factors and mortality associated with subsequent carbapenem-resistant Enterobacterales (CRE) infection among hematological malignancies (HM) patients colonized with CRE is limited.

METHODS

HM patients were screened for rectal CRE. A retrospective case-control study of subsequent CRE infection among HM patients colonized with CRE was conducted between January 1st, 2020 and January 31st, 2022. Cases were defined as CRE colonized patients with subsequent infection and controls were those without infection. Bacterial identification was performed using MALDI Biotyper and antimicrobial susceptibility testing of strains was carried out using the VITEK 2 system or standard broth microdilution method. Logistic analysis was used for analyzing associated factors and Kaplan-Meier method was used for survival estimates.

RESULTS

A total of 953 HM patients were screened for rectal CRE and 98 (10.3%, 98/953) patients were colonized with CRE. Among the 98 colonized patients, 18 (18.4%, 18/98) patients developed subsequent infection. Most of the colonizing CRE isolates were Klebsiella pneumoniae (50.0%, 27/54), followed by Escherichia coli (27.8%, 15/54) and Enterobacter cloacae (9.3%, 5/54). As for the subsequent infecting CRE isolates, the dominated species was K. pneumoniae (55.6%, 10/18), followed by E. coli (33.3%, 6/18) and others (11.2%, 2/18). Receiving proton pump inhibitors and admission to ICU (P < 0.05) were the associated factors. Patients with subsequent CRE infection had significant higher mortality (33.3% vs 2.8%, P = 0.001) and shock was an associated factor (P = 0.008).

CONCLUSIONS

Klebsiella pneumoniae was the dominate colonizing species and subsequent infecting species among HM patients with CRE colonization. Receiving proton pump inhibitors and admission to ICU increased the risk of subsequent CRE infection among CRE colonized HM patients. Implementing strict infection control measures targeting those high- risk patients may prevent subsequent CRE infection.

Synergistic antibacterial activity of silver nanoparticles biosynthesized by carbapenem-resistant Gram-negative bacilli

Nanotechnology is being investigated for its potential to improve nanomedicine for human health. The purpose of this study was to isolate carbapenemase-producing Gram-negative bacilli (CPGB), investigate the presence of carbapenemase resistance genes, determine their antibiogram and ability to biosynthesise silver nanoparticles (Ag NPs), and estimate the antibacterial activity of Acinetobacter baumannii-biosynthesised Ag NPs on CPGB alone and in combination with antibiotics. A total of 51 CPGBs were isolated from various specimens in the study. The automated Vitek-2 system was used to identify and test these strains' antimicrobial susceptibilities. The carbapenemase resistance genes were identified using a polymerase chain reaction (PCR). Under the CPGB, A. baumannii could biosynthesise Ag NPs. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and field emission scanning electron were used to characterise Ag NPs. The antibacterial activity of Ag NP alone and in combination with antibiotics against CPGB was determined using the broth microdilution method, and their synergistic effect was determined using the checkerboard assay. bla_NDM and bla_OXA-48 were the most commonly reported, and 90% of the isolates produced multiple carbapenemase genes. Tigecycline proved to be the most effective anti-CPGB antibiotic. Isolates with more resistance genes were more resistant to antibiotics, and isolates with three genes (42%) had the most extensively drug-resistant patterns (38%). A significant relationship was discovered between genetic and antibiotic resistance patterns. Only A. baumannii produced Ag NPs out of all the isolates tested. Ag NPs with a size of 10 nm were confirmed by UV–visible spectroscopy, FT-IR, XRD, and TEM analysis. The Ag NPs were effective against CPGB, with minimum inhibitory concentrations ranging from 64 to 8 μg/ml on average. Surprisingly, the combination of Ag NPs and antibiotics demonstrated synergistic and partial synergistic activity (fractional inhibitory concentration between 0.13 and 0.56) against CPGB, as well as a significant reduction in antibiotic concentrations, particularly in the case of A. baumanii versus ceftriaxone (1024 to 4 μg/ml). The notable synergistic activity of Ag NPs with antibiotics represents a valuable nanomedicine that may find clinical application in the future as a combined remedy.

Prevalence and Molecular Characterization of Extended Spectrum β-Lactamase and Carbapenemase-Producing Enterobacteriaceae Isolates from Bloodstream Infection Suspected Patients in Addis Ababa, Ethiopia

Background

Production of Extended spectrum beta-lactamase (ESBL) and Carbapenemase is the most common strategy for drug resistance in clinical isolates of Enterobacteriaceae. This study was conducted to determine the magnitude of ESBL and Carbapenemase production (CPE) among clinical isolates of Enterobacteriaceae causing bloodstream infections (BSI) in Ethiopia.

Methods

A cross-sectional study was performed from September 2018 to January 2019 in Ethiopia. A total of 2397 BSI suspected patients were enrolled and blood culture was performed using a BacT/Alert instrument in combination with conventional methods for identification. After antimicrobial susceptibility test, phenotypic confirmation of ESBLs was done by combined disc-diffusion. Meanwhile carbapenemase production was done by modified carbapenem inactivation method. Multiplex PCR was conducted to detect the presence of bla_CTX-M,bla_SHV,bla_TEM, bla_KPC and bla_NDM genes.

Results

A total of 104 (4.3%) Enterobacteriaceae were isolated from 2397 BSI suspected patients. Klebsiella pneumoniae (55/104, 52%) was the predominant isolate followed by E. coli, (19.2%, 20/104) and K.oxytoca (17.3%, 18/104). ESBL and carbapenemase production were observed from 70 (67.3%, 57.4 −76.2% at 95% CI) and 8 (7.7%, 3.4–14.6% at 95% CI) isolates respectively. The highest frequency of ESBL and carbapenemase production was observed in K. pneumoniae 78.2% (43/55) and 9.1% (5/55), respectively. All the 70 isolates confirmed as ESBL producers harbored at least one of the ESBL genes and the majority of them carried multiple beta-lactamase genes (84.3%), where bla_CTX-M, type was the most predominant (67.3%). Similarly, the entire eight isolates positive for carbapenemase carried bla_NDM but none of them carried bla_KPC.

Conclusion

In our study, the rate of ESBL production among BSI-causing Enterobacteriaceae was alarming and most of the isolates carried multiple types of ESBL genes. A significant magnitude of CPE isolates causing BSI was recorded.

Prevalence and characterisation of carbapenemase encoding genes in multidrug-resistant Gram-negative bacilli

Background

Emerging worldwide in the past decade, there has been a significant increase in multidrug-resistant bacteria from serious nosocomial infections, especially carbapenemase-producing Gram-negative bacilli that have emerged worldwide. The objective of this study is to investigate carbapenem resistance in Gram-negative bacilli bacteria using phenotypic detection, antimicrobial resistance profiles and genotypic characterisation methods.

Methods

200 Gram-negative bacilli isolates were collected from different clinical specimens. All clinical samples were exposed to isolation and identification of significant pathogens applying bacteriological examination and an automated Vitek-2 system. The isolates were subjected to susceptibility tests by the Vitek-2 automated system and those isolates that were resistant to beta-lactam drugs, including carbapenems, third-generation cephalosporines or cefoxitin, were selected for phenotyping using Carba plus disc system assay for detection of carbapenemase-producing isolates. These isolates were further confirmed by molecular detection. PCR was used for the detection carbapenem-resistant genes (OXA-48, IMP, NDM, VIM, and KPC).

Results

110 (55%) of 200 Gram-negative bacilli were identified as beta-lactam-resistant isolates. The frequency of carbapenem-resistant isolates was calculated to be 30.9% (n = 34/110). A collection totalling 65/110 (59%) isolates were identified as carbapenemase producers by phenotypic method. Moreover, among the 65 carbapenemase-producing Gram-negative isolates with a positive phenotype-based result, 30 (46%), 20 (30%) and 18 (27%) isolates were positive for OXA-48, KPC and MBL enzymes, respectively, as well as the production of 27% of AmpC with porin loss. Tigecycline was the most effective antibiotic that affected 70% of MDR isolates, but high rates of resistance were detected to other tested antimicrobials. Of interest, a high incidence of MDR, XDR and PDR profiles were observed among all carbapenemase-producing isolates. 36% (24/65) of the tested isolates were MDR to 3 to 5 antimicrobial classes. 29% (17/65) of the recovered isolates were XDR to 6 to 7 antimicrobial classes. Alarmingly, 24% (16/65) of isolates displayed PDR to all the tested 8 antimicrobial classes. Genotype assay, including 53 phenotypically confirmed carbapenemase-producing isolates of Gram-negative bacilli, found 51(96%) isolates were harbouring one or more genes. The most common carbapenemase gene was bla_NDM 83% (44/53) followed by bla_OXA-48 75% (40/53), bla_VIM 49% (26/53) and bla_IMP 43% (23/53), while the gene bla_KPC was least frequent 7% (4/53). 92% (46/51) of isolates were involved in the production of more than one carbapenemase gene.

Conclusion

This study demonstrated the emergence of carbapenemase-producing Gram-negative pathogens implicated in healthcare-related infections. Accurate identification of carbapenem-resistant bacterial pathogens is essential for patient treatment, as well as the development of appropriate contamination control measures to limit the rapid spread of pathogens. Tigecycline exhibited potent antimicrobial activity against MDR, XDR and PDR-producing strains that establish a threatening alert which indicates the complex therapy of infections caused by these pathogens.

Detection of NDM-1 and VIM Genes in Carbapenem-Resistant Klebsiella pneumoniae Isolates from a Tertiary Health-Care Center in Kathmandu, Nepal

BACKGROUND

Klebsiella pneumoniae is one of the leading causes of nosocomial infections. Carbapenems are used as the last resort for the treatment of multidrug resistant Gram-negative bacterial infections. In recent years, resistance to these lifesaving drugs has been increasingly reported due to the production of carbapenemase. The main objective of this study was to detect the carbapenem-resistant genes blaNDM-1 and blaVIM in K. pneumoniae isolated from different clinical specimens.

METHODS

A total of 585 clinical specimens (urine, pus, sputum, blood, catheter tips, and others) from human subjects attended at Annapurna Neurological Institute and Allied Sciences, Kathmandu were obtained in the period between July 2018 and January 2019. The specimens were isolated and identified for K. pneumoniae. All K. pneumoniae isolates were processed for antimicrobial susceptibility testing (AST) using the disk diffusion method. The isolates were further phenotypically confirmed for carbapenemase production by the modified Hodge test (MHT) using imipenem (10 μg) and meropenem (10 μg) discs. Thus, confirmed carbapenemase-producing isolates were further screened for the production of blaNDM-1 and blaVIM using conventional polymerase chain reaction (PCR).

RESULTS

Among the clinical isolates tested, culture positivity was 38.29% (224/585), and the prevalence of K. pneumoniae was 25.89% (58/224). On AST, K. pneumoniae exhibited resistance toward carbapenems including ertapenem, meropenem, and imipenem, while it showed the highest susceptibility rate against to tigecycline (93.1%; 54/58). Overall, AST detected 60.34% (35/58) carbapenem-resistant isolates, while the MHT phenotypically confirmed 51.72% (30/58) isolates as carbapenemase-producers and 48.28% (28/58) as carbapenemase nonproducers. On subsequent screening for resistant genes among carbapenemase-producers by PCR assay, 80% (24/30) and 3.33% (1/30) isolates were found to be positive for blaNDM-1 and blaVIM, respectively. In the same assay among 28 carbapenem nonproducing isolates, 9 (32.14%) isolates were positive for blaNDM-1 gene while none of them were tested positive for blaVIM gene.

CONCLUSIONS

Molecular detection of resistant genes provides greater specificity and sensitivity than those with conventional techniques, thus aiding in accurate identification of antimicrobial resistance and clinical management of the disease.

Detection and characterization of carbapenem resistant Gram-negative bacilli isolates recovered from hospitalized patients at Soba University Hospital, Sudan

Background

Antimicrobial resistance (AMR) poses a complex threat to global health security and universal health coverage. Recently, nosocomial infections with carbapenemase-producing Gram-negative bacilli (GNB) is increasing worldwide. We report the molecular characterization and detection of genes associated with carbapenemase producing Gram negative bacteria isolated from hospitalized patients at Soba University Hospital (SUH) in Khartoum State, Sudan.

Results

Between October 2016 and February 2017, a total of 206 GNB clinical specimens were collected from hospitalized patients in SUH. Of 206 carbapenem resistance isolates, 171 (83 %) were confirmed as phenotypically resistant and 121 (58.7 %) isolates harboured one or more carbapenemase genes. New Delhi metallo-β-lactamase (NDM) types were the most predominant genes, blaNDM 107(52 %), followed by blaIMP 7 (3.4 %), blaOXA-48 5(2.4 %) and blaVIM 2 (0.9 %). Co-resistance genes with NDM producing GNB were detected in 87 (81.3 %) of all blaNDM producing isolates. NDM-1 was the most frequent subtype observed in 75 (70 %) blaNDM producing isolates. The highest percentage of resistance was recorded in ampicillin (98 %), cephalexin (93.5 %) amoxicillin clavulanic acid (90 %), cefotaxime (89.7 %), ceftriaxone (88.4 %), ceftazidime (84.2 %), sulfamethoxazole-trimethoprim (78.4 %) and nitrofurantoin (75.2 %), aztreonam (66 %) and temocillin (64 %). A close correlation between phenotypic and carbapenemase genes detection in all GNB was observed.

Conclusions

The frequency of carbapenemase producing bacilli was found to be high in SUH. NDM was found to be the most prevalent carbapenemase gene among clinical isolates. Close surveillance across all hospitals in Sudan is required. The relative distribution of carbapenemase genes among GNB in nosocomial infections in Africa needs to be defined.

What are acute NHS trusts in England doing to prevent the cross-border spread of carbapenem-resistant Enterobacteriaceae?

Background

Carbapenem-resistant Enterobacteriaceae (CRE) pose a significant threat to global public health as these organisms have the potential to cause infections which are easily spread and are associated with high mortality rates.

Aim/Objective

The aim of this study was to establish which screening strategies acute NHS trusts in England have chosen to adopt and whether or not that strategy has prevented or is likely to prevent the cross-border spread of CRE.

Methods

All acute NHS trusts in England were invited to participate in a multicentre quantitative study. Participants were asked to complete a questionnaire relating to their local CRE screening protocol.

Findings/Results

Of the 91 participating trusts, 83 (91.2%) adhere to Public Health England (2013) guidance. However, only 22 (24.2%) trusts have adopted the European Centre for Disease Prevention and Control (2016) recommendations. In total, 31 (34.1%) trusts reported incidences of person-to-person transmission, of which 45.2% were related to foreign travel. Furthermore, 31 (34.1%) trusts reported that patients who have had an admission to a hospital in the UK not known to have a high prevalence of healthcare-associated CRE in the last 12 months had screened positive.

Discussion

This study has demonstrated that inter-hospital transmission is as much of a concern as cross-border spread. Mandatory participation in enhanced surveillance could provide PHE with the epidemiological evidence required to support this stance and help to develop new national guidance.

Global genotype distribution of human clinical isolates of New Delhi metallo-β-lactamase-producing Klebsiella pneumoniae; A systematic review

BACKGROUND AND AIM

The global rise of antimicrobial resistance among bacterial strains is a rapidly growing challenge and is becoming a major public health concern. This study documents the worldwide spread and genotype distribution of human clinical isolates of New Delhi metallo-β-lactamase-producing Klebsiella pneumoniae (NPKP).

METHODS

Several international databases, including Web of Science, Embase and Medline were searched (2010 - 2019) to identify studies addressing the frequency of NPKP regionally or worldwide.

RESULTS

Of 4779 articles identified, 202 studies fulfilled the eligibility criteria and were included in our analysis. The frequency of NPKP in Asia, Europe, America, Africa and Oceania was 64.6%, 20.1%, 9.0%, 5.6% and 0.4%, respectively. The most prevalent sequence types (STs) among NPKP were ST11, ST290, ST147, ST340, ST15, ST278 and ST14 based on published studies.

CONCLUSION

The dissemination of bla_NDM variants in different STs among NPKP in the various region of world is a serious concern to public health. The prevalence of NPKP should be controlled by comprehensive infection control measures and optimization of antibiotic therapy.

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 New Delhi Metallo-Beta-Lactamase (NDM) and Klebsiella pneumoniae Carbapenemase (KPC) Production by Escherichia coli and Klebsiella pneumoniae in Southern Vietnam and Appropriate Methods of Detection: A Cross-Sectional Study

Carbapenemase-producing Enterobacteriaceae (CPE) are well known to cause many serious infections resulting in increasing mortality rate, treatment cost, and prolonged hospitalization. Among the widely recognized types of carbapenemases, New Delhi β-lactamase (NDM) and Klebsiella pneumoniae carbapenemase (KPC) are the most important enzymes. However, in Vietnam, there are only scattered reports of CPE due to the lack of simple and affordable methods that are suitable to laboratory conditions. This study aims to survey the characteristics of carbapenem-resistant E. coli and K. pneumoniae (CR-E/K) at two hospitals in Southern Vietnam and perform some simple methods to detect the two enzymes. A total of 100 CR-E/K strains were collected from clinical isolates of Gia Dinh People's Hospital and Dong Nai General Hospital, Vietnam, from November 2017 to May 2018. The patient-related information was also included in the analysis. We conducted real-time polymerase chain reaction (PCR), Modified Hodge Test (MHT), and combined disk test (CDT) on all isolates. Carbapenemase-encoding genes were detected in 47 isolates (36 NDM, 10 KPC, and one isolate harboring both genes). The E. coli strain carrying simultaneously these two genes was the first case reported here. Most of isolates were collected from patients in ICU, Infectious Disease Department, and Department of Urologic Surgery. Urine and sputum were two common specimens. The true positive rate (sensitivity, TPR) and specificity (SPC) of the imipenem–EDTA (ethylen diamine tetra acetic acid) for NDM detection and the imipenem–PBA (phenylboronic acid) for KPC detection on E. coli were 93.8%, 97.1% and 66.7%, 95.7%, respectively. Meanwhile, the imipenem–EDTA for NDM detection and the imipenem–PBA for KPC detection among K. pneumonia achieved 90.5%, 100% and 100%, 92.9% TPR and SPC, respectively. However, MHT showed low sensitivity and specificity. Our findings showed that CP-E/K were detected with high prevalence in the two hospitals. We suggest that CDT can be used as a low-priced and accurate method of detection.

Genetic support of carbapenemases in double carbapenemase producer Klebsiella pneumoniae isolated in the Arabian Peninsula

Enterobacteriaceae co-producing NDM- and OXA-48-type carbapenemases were encountered in higher frequency in the United Arab Emirates (UAE) than in the neighboring countries in our earlier study. The aim of this investigation was to characterize the seven double carbapenemase producer Klebsiella pneumoniae found in the region to assess factors contributing to their emergence. Three K. pneumoniae ST14 isolated in the UAE harboring bla_NDM-1 on IncHI1b and bla_OXA-232 on IncColE plasmids were clonally related. Furthermore, two K. pneumoniae from the UAE, ABC106 and ABC137 belonged to ST307 and ST1318, respectively. ABC106 carried bla_NDM-1 on IncHI1b, and bla_OXA-162 on IncL/M plasmids, whereas ABC137 possessed bla_NDM-1 on IncX3 and bla_OXA-48 on IncL/M plasmids. The double carbapenemase-producing K. pneumoniae from Oman (OMABC109) and Saudi Arabia (SA54) belonged to ST11 and ST152, respectively. OMABC109 harbored bla_NDM-1 on an IncHI1b plasmid highly similar to the NDM-plasmid of ABC106 and carried a chromosomally coded bla_OXA-181 located on Tn2013. SA54 possessed a bla_NDM-1 on an IncFIb/FII plasmid and a bla_OXA-48 on an IncL/M plasmid. Based on these findings, clonal spread and horizontal transfer of carbapenemase genes located on transposons or self-transmissible plasmids contributed equally to the emergence of double carbapenemase-producing Enterobacteriaceae in the region.

Inhibitory effect of soy saponins on the activity of β-lactamases, including New Delhi metallo-β-lactamase 1

β-Lactamase-producing bacteria encode enzymes that inactivate β-lactam antibiotics by catalyzing the hydrolysis of the β-lactam ring. Crude soy saponins were observed to have synergistic effects on the antimicrobial activity of β-lactam antibiotics against β-lactamase-producing Staphylococcus aureus strains. Furthermore, the activities of β-lactamases derived from Enterobacter cloacae, Escherichia coli, and S. aureus were decreased significantly in the presence of crude soy saponins. This inhibitory effect was also observed against the New Delhi metallo-β-lactamase 1 (NDM-1), an enzyme whose activity is not inhibited by the current β-lactamase inhibitors. The synergistic effect on the antimicrobial activity of β-lactam antibiotics by crude soy saponins was thought to result from the inhibition the β-lactamase activity. The components of crude soy saponins include several kinds of soyasaponins and soyasapogenols. It was revealed that soyasaponin V has the highest inhibitory activity against NDM-1. The combined use of soy saponins with β-lactam antibiotics is expected to serve as a new therapeutic modality, potentially enhancing the effectiveness of β-lactam antibiotics against infectious diseases caused by β-lactamase-producing bacteria, including those encoding NDM-1.

Performance of "RESIST-3 O.K.N. K-SeT" immunochromatographic assay for the detection of OXA-48 like, KPC, and NDM carbapenemases in Klebsiella pneumoniae in Turkey

In this study, the performance of the “RESIST-3 O.K.N. K-SeT” (Coris BioConcept, Gembloux, Belgium) immunochromatographic assay was evaluated in 132 Klebsiella pneumoniae comprising 102 carbapenem resistant and 30 carbapenem susceptible isolates. Genotypically known isolates of Gram negative bacteria (n = 22) including various species were also tested by the assay as controls. The isolates tested by the immunochromatographic assay and also were run PCR for bla_KPC, bla_IMP, bla_VIM, bla_NDM, and bla_OXA-48. The rates of bla_NDM, bla_OXA-48, and bla_KPC in carbapenem resistant isolates were found at 52.9%, 39.2%, and 2.0%, respectively. Both bla_NDM and bla_OXA-48 were found in six (5.9%) isolates. The results of the assay showed 100% concordance with those obtained by PCR in 132 K. pneumoniae. The agreement between the two methods was found to be identical at the isolate level. The assay also correctly detected all genotypically known isolates of Escherichia coli, Serratia marcescens, Citrobacter freundii, Enterobacter cloacae, K. pneumoniae carrying bla_KPC, bla_NDM, and/or bla_OXA-48. On the other hand, the assay did not exhibit any cross-reaction in control isolates harboring bla_IMP and bla_VIM. We conclude that the RESIST-3 O.K.N. K-SeT is a reliable, rapid, and user friendly test and we recommend it for routine diagnostic laboratories.

Prevalence and risk factors for CTX-M gram-negative bacteria in hospitalized patients at a tertiary care hospital in Kilimanjaro, Tanzania

Emergence and spread of extended spectrum beta-lactamase (ESBL)-producing gram-negative bacteria, mainly due to CTX-M, is a major global public health problem. Patients infected with ESBL-producing gram-negative bacteria have an increased risk of treatment failure and death. We investigated the prevalence and risk factors for CTX-M gram-negative bacteria isolated from clinical specimens of patients hospitalized at a tertiary care hospital in Kilimanjaro, Tanzania. Isolated gram-negative bacteria from inpatients admitted at Kilimanjaro Christian Medical Centre (KCMC) between August 2013 and August 2015 were fully genome sequenced. The prevalence of ESBL-producing gram-negative bacteria was determined based on the presence of bla_CTX-M. The odds ratio (OR) and risk factors for ESBL-producing gram-negative bacteria due to CTX-M were assessed using logistic regression models. The overall CTX-M prevalence (95% CI) was 13.6% (10.1–18.1). Adjusted for other factors, the OR of CTX-M gram-negative bacteria for patients previously hospitalized was 0.26 (0.08–0.88), p = 0.031; the OR for patients currently on antibiotics was 4.02 (1.29–12.58), p = 0.017; the OR for patients currently on ceftriaxone was 0.14 (0.04–0.46), p = 0.001; and the OR for patients with wound infections was 0.24 (0.09–0.61), p = 0.003. The prevalence of ESBL-producing gram-negative bacteria due to CTX-M in this setting is relatively low compared to other previous reports in similar settings. However, to properly stop further spread in the hospital, we recommend setting up a hospital surveillance system that takes full advantage of the available next-generation sequencing facility to routinely screen for all types of bacterial resistance genes.

Emergence and mechanism of carbapenem-resistant Escherichia coli in Henan, China, 2014

The emergence and dissemination of carbapenem-resistant Escherichia coli (E. coli) strains is a main risk for global public health, but little is known of carbapenemase producing E. coli in Henan, China. The study was undertaken to investigate the prevalence and mechanism of carbapenem-resistant E. coli strains in a hospital in Xinxiang, Henan, China, 2014. A total of 5 carbapenemase-producing E. coli strains were screened from 1014 isolates. We found that they were all resistant to meropenem and imipenem. Amikacin showed the best sensitivity, with gentamicin coming up next. The positive rate of bla_NDM was 80% (4/5). The sequencing results showed that two isolates belonged to bla_NDM-1 whereas other 2 isolates carried the bla_NDM-5. Other carbapenemase genes including bla_IMP,bla_VIM, bla_KPC and bla_OXA-48 were not detected. The bla_CTX-M-15,bla_TEM-1,sul2, aad, and aac(6")-Ib-cr were also detected. MLST analysis showed that NDM-producing E. coli were sporadic. Conjugation test indicated bla_NDM could be transferred. In conclusion, the bla_NDM was the principal resistance mechanism of carbapenem-resistant E. coli in the hospital, Henan, China.

Identification of Carbapenem-Resistant Klebsiella pneumoniae with Emphasis on New Delhi Metallo-Beta-Lactamase-1 (blaNDM-1) in Bandar Abbas, South of Iran

BACKGROUND AND OBJECTIVE

The spread of carbapenem-resistant Klebsiella pneumoniae especially bla_NDM-1-carrying isolates is a great concern worldwide. In this study we describe the molecular basis of carbapenem-resistant K. pneumoniae in three teaching hospitals at Bandar Abbas, south of Iran.

MATERIALS AND METHODS

A total of 170 nonduplicate clinical isolates of K. pneumoniae were investigated. Antimicrobial susceptibility test was performed by disc diffusion method. PCR was carried out for detection of carbapenemase (bla_KPC, bla_IMP, bla_VIM, bla_NDM, bla_SPM, bla_OXA-48, and bla_OXA-181) and extended-spectrum β-lactamase (bla_CTX-M, bla_SHV, bla_TEM, bla_VEB, bla_GES, and bla_PER). Clonal relatedness of bla_NDM-1-positive isolates was evaluated by multilocus sequence typing (MLST).

RESULTS

Tigecycline was the most effective antimicrobial agent with 96.5% susceptibility. In addition, 6.5% of the isolates were carbapenem resistant. Bla_NDM-1 was identified in four isolates (isolate A-D) and all of them were multidrug-resistant. MLST revealed that bla_NDM-1-positive isolates were clonally related and belonged to two distinct clonal complexes, including sequence type (ST) 13 and ST 392. In addition to bla_NDM-1, isolate A coharbored bla_SHV-11, bla_CTX-M-15, and bla_TEM-1, isolate B harbored bla_SHV-11 and bla_CTX-M-15, and isolates C and D contained both bla_SHV-1 and bla_CTX-M-15.

CONCLUSION

Our results indicate that NDM-1-producing K. pneumoniae ST 13 and ST 392 are disseminated in our region. Moreover, one of our major concerns is that these isolates may be more prevalent in the near future. Tracking and urgent intervention is necessary for control and prevention of these resistant isolates.