High Prevalence of CTX-M-15-Type Extended-Spectrum β-Lactamase Among AmpC β-Lactamase-Producing Klebsiella pneumoniae Isolates Causing Bacteremia in Korea

Monitoring of antimicrobial resistance in respiratory tract pathogens during the COVID-19 pandemic: A retrospective study

To understand the distribution and antimicrobial resistance (AMR) of pathogens in respiratory samples in Changle District People's Hospital in Fujian Province in recent years, and provide empirical guidance for infection control and clinical treatment in the region. A retrospective analysis was conducted on 5137 isolates of pathogens from respiratory samples collected from 2019 to 2022. The AMR patterns were systematically analyzed. For research purposes, the data was accessed on October 12, 2023. A total of 3517 isolates were included in the study, including 811 (23.06%) gram-positive bacteria and 2706 (76.94%) gram-negative bacteria. The top 3 gram-positive bacteria were Staphylococcus aureus with 455 isolates (12.94%), Streptococcus pneumoniae with 99 isolates (2.81%), and Staphylococcus hemolytic with 99 isolates (2.81%). The top 3 gram-negative bacteria were Klebsiella pneumoniae with 815 isolates (23.17%), Pseudomonas aeruginosa with 589 isolates (16.75%), and Acinetobacter baumannii with 328 isolates (9.33%). The proportion of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and K pneumoniae fluctuated between 41.9% and 70.5%, and 18.6% and 20.9%, respectively. The resistance rates of E coli, K pneumoniae, P aeruginosa, and A baumannii to carbapenems were 2.36%, 8.9%, 18.5%, and 19.6%, respectively. The prevalence of methicillin-resistant S aureus (MRSA) was 48.55%, but it decreased to 38.4% by 2022. The resistance rate of Staphylococcus haemolyticus to methicillin was 100%, and 1 case of vancomycin-resistant strain was detected. K pneumoniae, P aeruginosa, A baumannii, and S aureus are the main pathogens in respiratory samples. Although the resistance rates of some multidrug-resistant strains have decreased, ESBL-producing Enterobacteriaceae, carbapenem-resistant bacteria have still increased. Therefore, it is necessary to strengthen the monitoring of pathogen resistance, promote rational use of antibiotics, and promptly report findings.

Phenotypic and molecular characterization of extended-spectrum β-lactamase/AmpC- and carbapenemase-producing Klebsiella pneumoniae in Iran

BACKGROUND

The objective of the current study is to evaluate the phenotypic and molecular characterization of ESBL/AmpC- and carbapenemase-producing K. pneumoniae isolates in Iran.

METHODS

From October 2018 until the end of April 2020, different clinical samples were collected and K. pneumoniae isolates were identified using conventional biochemical tests and PCR assay. Antibiotic susceptibility pattern was determined using the Kirby-Bauer disk diffusion method. Modified Hedge Test (MHT) was applied to the identification of carbapenemase-producing K. pneumoniae. ESBL and AmpC-producing K. pneumoniae were detected using Double Disc Test (DDT) and Disc Potentiation Test (DPT), respectively. The presence of carbapenemase, ESBL, and AmpC encoding genes was screened by Polymerase Chain Reaction (PCR) assay.

RESULTS

A total of 100 K. pneumoniae isolates were collected. K. pneumoniae isolates had the highest resistance rate to cefazolin (66%) and cefotaxime (66%). Meropenem and amikacin with sensitivity rates of 76% and 69% were the most effective antimicrobial agents on K. pneumoniae isolates. It was found that 12 (12%), 27 (27%), and 9 (9%) K. pneumoniae isolates were positive in MHT, DDT, and DPT tests, respectively. Among the carbapenemase-encoding genes, bla_OXA-48 (24%) and bla_IMP (13%) genes had the highest frequency, while bla_KPC and bla_GIM genes were not detected among K. pneumoniae isolates. bla_TEM (48%) and bla_CMY (8%) genes had the highest frequency among ESBL and AmpC β-lactamase-encoding genes, respectively.

CONCLUSIONS

It is vital to adopt effective control strategies for K. pneumoniae infections and ensure rapid identification of antibiotic resistance profile.

Prevalence and antimicrobial resistance of Klebsiella species isolated from clinically ill companion animals

Background

Klebsiella spp. is an important conditional pathogen in humans and animals. However, due to the indiscriminate use of antibiotics, the incidence of antimicrobial resistance has increased.

Objectives

The purpose of this study was to investigate antimicrobial resistance in strains of Klebsiella strains and the phylogenetic relatedness of extended-spectrum cephalosporin (ESC)-resistance among Klebsiella strains isolated from clinically ill companion animals.

Methods

A total of 336 clinical specimens were collected from animal hospitals. Identification of Klebsiella species, determination of minimum inhibitory concentrations, detection of ESC resistance genes, polymerase chain reaction-based replicon typing of plasmids by conjugation, and multilocus sequence typing were performed.

Results

Forty-three Klebsiella strains were isolated and, subsequently, 28 were identified as K. pneumoniae, 11 as K. oxytoca, and 4 as K. aerogenes. Eleven strains were isolated from feces, followed by 10 from ear, 7 from the nasal cavity, 6 from urine, 5 from genitals, and 4 from skin. Klebsiella isolates showed more than 40% resistance to penicillin, cephalosporin, fluoroquinolone, and aminoglycoside. ESCresistance genes, CTX-M groups (CTX-M-3, CTX-M-15, and CTX-M-65), and AmpC (CMY-2 and DHA-1) were most common in the K. pneumoniae strains. Some K. pneumoniae carrying CTX-M or AmpC were transferred via IncFII plasmids. Two sequence types, ST709 and ST307, from K. pneumoniae were most common.

Conclusions

In conclusion, this is the first report on the prevalence, ESCresistance genotypes, and sequence types of Klebsiella strains isolated from clinically ill companion animals. The combination of infectious diseases and antimicrobial resistance by Klebsiella in companion animals suggest that, in clinical veterinary, antibiotic selection should be made carefully and in conjunction with the disease diagnosis.

Successful control of an extended-spectrum beta-lactamase-producing Klebsiella pneumoniae ST307 outbreak in a neonatal intensive care unit

BACKGROUND

In this study, we evaluated the genetic relatedness of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (ESBL-KPN) isolates from an outbreak in a neonatal intensive care unit (NICU) in August 2017, We implemented an active countermeasure to control this outbreak successfully.

METHODS

The incidence of healthcare-associated ESBL-KPN bacteremia was evaluated before and after initiating enhanced infection control (IC) practices in January 2018. Surveillance cultures were set up and monitored for neonates, medical personnel, and NICU environments. Molecular analyses, including pulse-field gel electrophoresis (PFGE), sequence typing, and ESBL genotyping, were performed for the isolated KPN strains.

RESULTS

After implementing the enhanced IC procedures, the healthcare-associated bacteremia rate decreased from 6.0 to 0.0 per 1000 patient-days. Samples from neonates (n = 11/15, 73.3%), medical personnel (n = 1/41, 2.4%), and medical devices and the environments (6/181, 3.3%) tested positive for ESBL-KPN in the surveillance cultures in December 2017. Active surveillance cultures revealed that 23 of 72 neonates who were screened (31.9%) were colonized with ESBL-KPN between January and March 2018. All the isolates demonstrated closely related PFGE patterns and were identified as ST307 strain carrying the CTX-M-15 gene.

CONCLUSIONS

Contaminated NICU environments and medical devices, as well as transmission by medical personnel, appeared to be the source of the outbreak of ESBL-KPN infection. We employed an enhanced IC strategy during January-March 2018 and successfully controlled the clonal outbreak of CTX-M-15-positive KPN. ST307 has emerged as an important bacteremia-causing pathogen in the NICU and should be carefully monitored.

Klebsiella pneumoniae: an increasing threat to public health

OBJECTIVES

This review fills the paucity of information on K. pneumoniae as a nosocomial pathogen by providing pooled data on epidemiological risk factors, resistant trends and profiles and resistant and virulent genes of this organism in Asia.

METHODS

Exhaustive search was conducted using PubMed, Web of Science, and Google scholar for most studies addressing the prevalence, risk factors, drug resistant-mediated genes and/or virulent factors of K. pneumoniae in Asia. Data extracted for meta-analysis were analyzed using comprehensive meta-analysis version 3. Trends data for the isolation rate and resistance rates were entered into Excel spread sheet and the results were presented in graphs.

RESULTS

The prevalence rate of drug resistance in K. pneumoniae were; amikacin (40.8%) [95% CI 31.9-50.4], aztreonam (73.3%) [95% CI 59.9-83.4], ceftazidime (75.7%) [95% CI 65.4-83.6], ciprofloxacin (59.8%) [95% CI 48.6-70.1], colistin (2.9%) [95% CI 1.8-4.4], cefotaxime (79.2%) [95% CI 68.0-87.2], cefepime (72.6) [95% CI 57.7-83.8] and imipenem (65.6%) [95% CI 30.8-89.0]. TEM (39.5%) [95% CI 15.4-70.1], SHV-11 (41.8%) [95% CI 16.2-72.6] and KPC-2 (14.6%) [95% CI 6.0-31.4] were some of the resistance mediated genes observed in this study. The most virulent factors utilized by K. pneumoniae are; hypermucoviscous phenotype and mucoviscosity-related genes, genes for biosynthesis of lipopolysaccharide, iron uptake and transport genes and finally, adhesive genes.

CONCLUSION

It can be concluded that, antimicrobial resistant in K. pneumoniae is a clear and present danger in Asia which needs strong surveillance to curb this menace. It is very important for public healthcare departments to monitor and report changes in antimicrobial-resistant isolates.

Risk factors of community-onset extended-spectrum β-lactamase-producing Klebsiella pneumoniae bacteraemia in South Korea using national health insurance claims data

BACKGROUND

Although it is essential to know the particular causes of antibiotic-resistant infections in the community, there is lack of evidence regarding risk factors for community-onset extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) bacteraemia in South Korea. As such, this study aimed to identify risk factors for community-onset ESBL-KP bacteraemia.

METHODS

From May 2016 to April 2017, patients with community-onset KP bloodstream infection (BSI) (n = 408) from six sentinel hospitals participating in the Global Antimicrobial Surveillance System in South Korea were included in this study. Risk factors of ESBL-KP BSI were assessed. Polymerase chain reaction and sequencing to identify genes encoding ESBLs and multi-locus sequence typing were performed.

RESULTS

Of the 408 patients with community-onset KP BSI, 70 (17%) had ESBL-KP BSI. Admission to a long-term-care hospital within the previous 3 months [odds ratio (OR) 5.7, 95% confidence interval (CI) 2.1-15.6; P = 0.001], previous use of trimethoprim/sulfamethoxazole (TMP/SMT; OR 11.5, 95% CI 2.7-48.6; P = 0.001) or extended-spectrum cephalosporin (OR 2.2, 95% CI 1.2-3.9; P = 0.01), and previous use of a urinary catheter (OR 2.3, 95% CI 1.1-4.5; P = 0.02) were independent risk factors for community-onset ESBL-KP BSI. ESBL-KP isolates most frequently carried the CTX-M-1 group ESBL (74%, n = 52). The most prevalent sequence type (ST) among the ESBL-KP isolates was ST48 (14%, n = 10). Among non-ESBL-KP isolates, ST23 was most prevalent (21%, n = 70).

CONCLUSION

Previous admission to a long-term-care hospital, use of a urinary catheter and use of TMP/SMT or extended-spectrum cephalosporin within the previous 3 months were identified as risk factors for community-onset ESBL-KP BSI. Strict antibiotic stewardship and infection control measures are needed for long-term-care hospitals.

Clonal Spread of Extended-Spectrum Cephalosporin-Resistant Enterobacteriaceae Between Companion Animals and Humans in South Korea

Extended-spectrum cephalosporin (ESC)-resistant Enterobacteriaceae is an increasingly important problem in both human and veterinary medicine. The aims of this study were to describe a comparative molecular characterization of Enterobacteriaceae carrying ESC resistance genes, encoding extended-spectrum β-lactamase (ESBL) and AmpC, isolated from human stool samples, rectal swabs from companion animals, and swabs from the environment of veterinarian hospitals in South Korea, and to examine their possible dissemination and transmission. The ESC resistance genes were identified by PCR and sequencing. Isolates with the predominant ESC resistance genes were assessed for their genetic relatedness by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. A total of 195 Escherichia coli and 41 Klebsiella pneumoniae isolates that exhibited ESC resistance were recovered on CHROMagar ESBL from human, companion animal, and the veterinary hospital environmental samples. In companion animals, most of the ESC resistance genes were bla_{CMY–2–like} (26.4%), followed by bla_{CTX –M–55} (17.2%) and bla_CTX–M–14 (16.1%), whereas bla_CTX–M–15 (28.6%) was predominant in human samples. The epidemiological relatedness of isolates carrying ESC resistance genes, including 124 E. coli and 23 K. pneumoniae isolates carrying CMY-2-like, DHA-1-like, or/and CTX-M-type, were analyzed by PFGE. The pulsotypes of five E. coli isolates (three from dogs and two from humans) carrying bla_{CMY–2–like}, which were attributed to sequence type 405, from different veterinary clinics showed >85% similarity. Our results indicate direct transmission and dissemination of ESC-resistant Enterobacteriaceae between humans and companion animals.

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.