Molecular epidemiology of carbapenem-resistant Klebsiella pneumoniae at a Turkish centre: Is the increase of resistance a threat for Europe?

Epidemiology and outcomes associated with MBL-producing Enterobacterales: A systematic literature review

The increasing prevalence of infections due to metallo-β-lactamase (MBL)-producing Enterobacterales poses a serious concern given the limited treatment options available. This systematic literature review (SLR) describes the molecular epidemiology, geographical distribution, and clinical outcomes of such infections. Systematic searches of literature published between January 2013 and May 2023 were performed, and 39 studies with an MBL sample size of ≥25 isolates and ≥2 well-defined outcomes were eligible. Most of the studies were from Asia (21/39) followed by Europe (11/39) and evaluated more than two species (24/39). Overall, the percentage of MBL-producing isolates ranged from 6.8%-100.0%. Among 6620 MBL-producers, the majority were from Europe (3837/6620; 58.0%), followed by Asia (2079/6620; 31.4%). New Delhi MBL (NDM)-producers (5668/6620; 85.6%) were the most frequent across all regions, with NDM-1 as the common variant. The majority of IMP-producing isolates (586/592; 99.0%) came from Asia, while the majority of VIM-producing isolates were found in Europe (322/371; 86.8%). Studies focused on MBL-specific outcomes (n = 28) reported reduced susceptibility (<80.0%) to most antimicrobials except for colistin and tigecycline. Six studies reported significantly longer hospital and/or ICU stay due to MBL-Enterobacterales compared to other infection groups. Common mortality measures reported were overall mortality (18.8%-57.0%; 9 studies), in-hospital mortality (11.1%-55.3%; 6 studies), and 30-day mortality (0%-36.4%; 7 studies). Previous antibiotic use (9 studies) and hospital and/or ICU stay (8 studies) were common risk factors for colonization/infection and mortality. Reporting of MBL prevalence across regions will provide a better understanding of the infection burden and prevent further spread.

Burden of severe infections due to carbapenem-resistant pathogens in intensive care unit

Intensive care units (ICU) for various reasons, including the increasing age of admitted patients, comorbidities, and increasingly complex surgical procedures (e.g., transplants), have become "the epicenter" of nosocomial infections, these are characterized by the presence of multidrug-resistant organisms (MDROs) as the cause of infection. Therefore, the perfect match of fragile patients and MDROs, as the cause of infection, makes ICU mortality very high. Furthermore, carbapenems were considered for years as last-resort antibiotics for the treatment of infections caused by MDROs; unfortunately, nowadays carbapenem resistance, mainly among Gram-negative pathogens, is a matter of the highest concern for worldwide public health. This comprehensive review aims to outline the problem from the intensivist's perspective, focusing on the new definition and epidemiology of the most common carbapenem-resistant MDROs (Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacterales) to emphasize the importance of the problem that must be permeating clinicians dealing with these diseases.

Ceftazidime - Avibactam susceptibility among carbapenem-resistant Enterobacterales in a pilot study in Turkey

This study aimed to detect carbapenemase genes and to determine the in vitro susceptibility of Ceftazidime-Avibactam (CZA) in Enterobacterales isolates. Carbapenemase genes were detected by polymerase chain reaction. CZA sensitivity of isolates was evaluated with broth microdilution (BMD) and disk diffusion methods. A total of 318 carbapenem-resistant Enterobacterales isolates were included. Most of the isolates (n = 290, 91.2%) were identified as Klebsiella pneumoniae. The most common carbapenemase type was OXA-48 (n = 82, 27.6%). CZA susceptibility was evaluated in 84 isolates with OXA-48 and KPC carbapenemase activity. Both BMD and disk diffusion methods revealed that 95.2% of the isolates were sensitive to CZA; whereas, 4 (4.76%) isolates were resistant to CZA. Among colistin resistant isolates, 96.5% (n = 80) of them were susceptible to CZA. Our study demonstrated high in vitro efficacy of CZA in Enterobacterales isolates producing OXA-48 carbapenemase. High susceptibility rates against colistin resistant isolates which generally are also pan drug resistant, makes CZA a promising therapeutic choice for difficult-to-treat infections. Due to its high correlation with the BMD, disk diffusion method is a suitable and more practical method in detecting CZA in vitro activity.

Antimicrobial Resistance Threats in the emerging COVID-19 pandemic: Where do we stand?

Antimicrobial resistance (AMR) continues to exert a substantial toll on the global health and world economy and is now expected to be hidden by COVID-19 for a while. The wrong consumption of antibiotics during the COVID-19 pandemic will raise disastrous effects on AMR management and antibiotic stewardship programs. This is related to the concerns extrapolated due to an increase in mortality rates in patients with bacterial coinfections. Importantly, the immune system of COVID-19 patients in regions with high AMR may be fighting on two fronts altogether, the virus and MDR bacteria. Current control policies to manage AMR and prioritization of antibiotic stewardship plans are mandatory during this pandemic. This review aims to discuss the rising concerns of the excess use of antibiotics in COVID-19 patients highlighting the role of bacterial coinfections in these patients. Types of prescribed antibiotics and the development of antibiotic resistance is addressed as well.

A Matched Case-Case-Control Study of the Impact of Clinical Outcomes and Risk Factors of Patients with IMP-Type Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae in Japan

IMP-type carbapenemase, found in various Gram-negative bacteria, has been increasingly detected worldwide. We aimed to study the outcomes and risk factors for acquisition of IMP-type carbapenemase-producing carbapenem-resistant Enterobacteriaceae (IMP-CRE), as this has not been evaluated in detail. We conducted a matched case-case-control study of patients from whom IMP-CRE isolates were obtained. All patients who tested positive for IMP-CRE were included; they were matched with patients with carbapenem-susceptible Enterobacteriaceae (CSE) and with controls at a ratio of 1:1:2. The risk factors for acquisition for the CRE and CSE groups and mortality rates, which were calculated using multivariate logistic regression models with weighting according to the inverse probability of propensity scores, were compared. In total, 192 patients (96 patients each in the CRE and CSE groups, with 130 Enterobacter cloacae isolates and 62 Klebsiella sp. isolates) were included. The IMP-11 type was present in 43 patients, IMP-1 in 33, and IMP-60 and IMP-66 in 1 each; 31 patients with CRE (32.3%) and 34 with CSE (35.4%) developed infections. Multivariate analysis identified the following independent risk factors: gastrostomy, history of intravenous therapy or hemodialysis, and previous exposure to broad-spectrum β-lactam antibiotics, including penicillin with β-lactamase inhibitors, cephalosporins, and carbapenems. In propensity score-adjusted analysis, mortality rates for the CRE and CSE groups were similar (15.0% and 19.5%, respectively). We found that IMP-CRE may not contribute to worsened clinical outcomes, compared to CSE, and gastrostomy, previous intravenous therapy, hemodialysis, and broad-spectrum antimicrobial exposure were identified as risk factors for CRE isolation. Fluoroquinolone and aminoglycosides are potentially useful antibiotics for IMP-CRE infections.

Detection of carbapenem-resistant Klebsiella pneumoniae strains harboring carbapenemase, beta-lactamase and quinolone resistance genes in intensive care unit patients

Aim: Carbapenem-resistant Klebsiella pneumoniae (CR-Kp) strains are important nosocomial pathogens worldwide. In this study, we aimed to reveal the antibiotic resistance of clinical CR-Kp strains and determine the presence of KPC, OXA-48, VIM and IMP carbapenemase genes. CTX-M-1, TEM-1, SHV-1 extended-spectrum beta-lactamase (ESBL) genes, qnrA, qnrB, qnrS plasmid-mediated quinolone resistance genes and sul1 and sul2 sulfonamide resistance genes provided molecular epidemiological data.

Methods: A total of 175 K. pneumoniae strains were isolated from clinical samples of patients hospitalised in an intensive care unit (ICU) betweent April and October 2017. The strains were identified with conventional methods, with VITEK 2 (BioMerieux, France) and MALDI-TOF MS (Bruker, USA). Antimicrobial susceptibilities were tested using the disc-diffusion method and E-test (BioMerieux, France). Antimicrobial resistance genes were investigated via real-time PCR in strains identified as CR-Kp.

Results: High frequencies of bla_TEM-1 (86.36%), bla_SHV-1 (86.36%), and bla_CTX-M-1 (95.45%) genes were found in CR-Kp strains. Morever, all three ESBL genes coexisted in 77.3% of all strains. bla_KPC was detected in 12 (54.55%) of the strains, and 4 of them which had an MIC> 16 μg/mL to imipenem showed bla_OXA-48 positivity as well. The qnrS gene determinant (86.36%) had the highest frequency, and strains carrying qnrA showed higher MICs for ciprofloxacin.

Conclusion: CR-Kp strains are able to develop different antimicrobial resistance patterns according to regional changes in antimicrobial therapeutic policies. Thus, it is important to monitor the regional molecular epidemiological data for efficient treatment.

Epidemiology of carbapenemase-producing Enterobacterales in the Middle East: a systematic review

Introduction: The Middle East is actually recognized as endemic for carbapenemases-producing Enterobacterales (CPE) including at least OXA-48-like and NDM-like.Areas covered: We performed a search of PubMed and Scopus using relevant keywords. We included peer-reviewed articles published only in English reporting any data on carbapenemase-producing bacteria from Middle East countries. The last literature search was performed on 26 October 2019. All studies describing carbapenemase-producing Enterobacterales isolated from humans, animals or environmental samples from the Middle East were included.Expert opinion: The Middle-East is considered an endemic region for CPE strains and the extensive international exchange could facilitate the spread of CPE from these countries to other parts of the Globe in which the prevalence of the CPE is low. The expansion of the Middle East conflict has been associated with the rapid collapse of the existing health care system of the concerned countries. Considering that Millions of refugees have fled their country, they could introduce these CPE strains in countries with low endemicity. In conclusion, the health care system actors should take in a count the endemicity of CPE in these countries and develop local surveillance programs to limit the spread of these MDR bacteria.

Retrospective evaluation of the patients with urinary tract infections due to carbapenemase producing Enterobacteriaceae

In this study, we aimed to investigate retrospectively the patients with carbapenem-resistant Enterobacteriaceae urinary tract infections (UTIs) in the terms of demographic findings, antibiotic sensitivity patterns and clinical features along with the treatment options. This study was performed at a tertiary-care educational university hospital. Adult (>18 years old) patients diagnosed with culture proven UTI due to carbapenem-resistant Klebsiella pneumoniae (between December 2016 to December 2017) were included in the study. Antimicrobial susceptibility testing of the isolates was performed with the VITEK 2 system (bioMérieux). Resistance to imipenem, ertapenem, and meropenem was tested by E-test (bioMérieux). The results were interpreted according to the EUCAST criteria. A total number of 100 patients (34% female, mean age 61.69 ± 1.65 years) were included in this study. One month all-cause mortality rate was 19%. Microbiologic eradication rate was 88.7% while it was significantly higher in combination therapy (65/70 vs. 14/19, p = 0.019) and carbapenem long-lasting (4 h) infusion subgroups (54/56 vs. 2/56, p = 0.005). Relapse and reinfection rates were 61.7 and 29.7%, respectively. Logistic regression analysis for mortality risk factors resulted as history of ertapenem usage (OR: 4.74, 95% CI: 0.678-33.201, p = 0.117), lack of microbiologic eradication (OR: 21.7, 95% CI: 1.906-247.375, p = 0.013) and ICU stay (OR: 54.8, 95% CI: 4.145-726.324, p = 0.002). Combination, carbapenem long-lasting infusion and double carbapenem therapies seem to result in higher microbiologic eradication rates and thus may effect the mortality rates of these group of patients. Randomized-controlled studies should be performed in this critical patient group to confirm these results.

Characterization of Klebsiella pneumoniae Coproducing KPC and NDM-1 Carbapenemases from Turkey

Aims: The emergence of multidrug-resistant and carbapenem-resistant Klebsiella pneumoniae has became a major public health threat. In this study, we describe the characteristics of isolates coproducing KPC and NDM-1 carbapenemases from patients hospitalized at an emergency unit in Ankara, Turkey, between January and August 2018. The isolates were characterized by antibiogram susceptibility, carbapenemase and extended-spectrum beta-lactamase production, plasmid-mediated colistin (COL) resistance, and high-level aminoglycoside resistance. Pulsed field gel electrophoresis (PFGE), sequencing, wzi typing, multilocus sequence typing, and plasmid analysis were used to investigate the epidemiological relationship between the isolates. Results: All isolates were found to be resistant to amoxicillin-clavulanic acid, piperacillin-tazobactam, cefotaxime, cefoxitin, cefuroxime, ceftazidime, cefepime, imipenem, meropenem, ertapenem, amikacin, gentamicin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole. The minimum inhibitory concentration values for imipenem, meropenem, and ertapenem were >32 μg/mL, and >256 μg/mL for amikacin and gentamicin, and two isolates were found to be susceptible to both tigecycline and COL. All strains were positive for SHV, CTX-M, and rmtC, and negative for mcr-1 genes. A/C and FIIA_S plasmids were found in all isolates. All isolates had the same PFGE pattern: wzi type 93 and ST15. Conclusion: Here, we have documented the characteristics of KPC- and NDM-1-coproducing isolates that harbored SHV, CTX-M, and rmtC and were typed as wzi 93 and ST15. We conclude that continuous monitoring of carbapenemases for unusual carbapenemase production is crucial to prevent the spread of these powerful isolates.

Characterization of blaNDM-harboring, multidrug-resistant Enterobacteriaceae isolated from seafood

Carbapenem-resistant Enterobacteriaceae (CRE) have evolved into a major challenge to antibiotic therapy worldwide. The problem is more confounding when wider dissemination of CRE occurs in the community and the environment. In this study, six bla_NDM-harboring Enterobacteriaceae, four Klebsiella pneumoniae, and two Escherichia coli, isolated from seafood, were characterized with respect to their antibiotic resistance and the genetic factors responsible for these resistances. The isolates were resistant to all β-lactam antibiotics, quinolones, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline and were susceptible to colistin, polymixin B, fosfomycin, and tigecycline. Four isolates harbored New Delhi metallo β-lactamase (bla_NDM-5 genes, while one isolate each harbored bla_NDM-1 and bla_NDM-2 genes, respectively. The bla_NDM genes in all the isolates were flanked by an upstream, truncated ISAba125, and downstream ble_MBL-trpF genes. Conjugation experiments showed that the NDM plasmids were readily transmissible. Further, the two bla_NDM-positive E. coli isolates belonged to the multidrug-resistant ST131 clone. This study highlights the growing danger of seafood as carriers of multidrug-resistant bacteria leading to their wider dissemination in the community.