Molecular characterization of extended spectrum β-lactamase-producing Enterobacteriaceae strains isolated from a tertiary care hospital

Extended-spectrum β-lactamase-producing Enterobacteriaceae from ready-to-eat foods: Genetic diversity and antibiotic susceptibility

Ready-to-eat (RTE) foods are widely marketed in China and are important components of everyday diet. In this study, a total of 2000 RTE food samples were analyzed, 252 (12.60%) of which were positive for Enterobacteriaceae, and 48 were identified as containing extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates. Furthermore, the antimicrobial resistance patterns of these isolates to 14 antimicrobial agents revealed that most isolates were resistant to aminoglycosides and β-lactam antibiotics. The TEM-type gene was prevalent in our isolates (79.17%). The isolates (n = 48) were classified into three clusters based on the ERIC-PCR results. Forty-eight sequence types were found without duplicates, revealing genetic variation and relatedness among isolates. Thus, the results demonstrated the presence of ESBL-producing Enterobacteriaceae in Chinese RTE foods. The results of this study provide insights into the spread of antibiotic-resistant strains and improve understanding of microbial risks.

The Phylogenetic Relatedness of bla NDM-1 Harboring Extended-Spectrum β-Lactamase Producing Uropathogenic Escherichia coli and Klebsiella pneumoniae in the North of Iran

Background

Escherichia coli and Klebsiella pneumoniae as an important part of Enterobacterales family are important causes of both community- and hospital-acquired infections. The present study aimed to investigate the prevalence of antibiotics resistance and molecular characteristics of uropathogenic isolates of E. coli and K. pneumoniae in Iranian patients.

Methods

This cross-sectional study performed on 223 Escherichia coli and 68 Klebsiella pneumoniae isolates obtained from hospitalized patients in the north of Iran. The isolates were identified by standard microbiologic tests and confirmed by API 20E strip. Disk diffusion method was applied to determine antibiotic susceptibility pattern. The presence of β-lactamases encoding genes was evaluated by PCR method. Analysis of the mutations and homology among sequences was done by the CLC sequence viewer (Qiagen, Denmark), and phylogenetic trees were constructed by the neighbor-joining method (Bootstrap: 1000 times).

Results

The overall rates of extended-spectrum β-lactamases (ESBLs)-producing E. coli and K. pneumoniae isolates were 37.7% and 32.4%, respectively. The overall presence of bla_SHV, bla_NDM-1, and bla_OXA-1 genes was detected in 16 (5.5%), 12 (4.1%), and 48 (16.4%) of isolates, respectively. The neighbor-joining analysis for E. coli KU985246.1 strain showed that the most related bla_NDM-1 sequences were from China, Singapore, UK, Thailand, and Bangladesh. While K. pneumoniae KU985245.1 strains were mostly related to bla_NDM-1 sequences form Myanmar, and China.

Conclusion

In summary, the remarkable rate of ESBL-producing uropathogenic Enterobacterales along with the first prevalence of NDM-1 β-lactamases can be a serious concern in our region.

CTX-M type extended-spectrum β-lactamase in Escherichia coli isolated from extra-intestinal infections in a tertiary care hospital in south India

Background & objectives:

Infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli carrying bla_CTX-M genes have been spreading globally, but there are geographical variations in the type of bla_CTX-M genes prevalent and there are scanty data from India. This study was conducted to determine the CTX-M type ESBLs in E. coli isolates obtained from clinical specimens from patients with extra-intestinal infections attending a tertiary care hospital in south India.

Methods:

ESBL-producing E. coli isolated from patients with extra-intestinal infections were subjected to PCR using CTX-M group-specific primers. From a representative isolate, full-length CTX-M-15 gene was amplified and sequenced. An internal fragment of this gene was sequenced in 10 representative isolates.

Results:

Of the 300 isolates of E. coli tested, 88 per cent carried CTX-M genes and bla_CTX-M-15 was the most dominant gene present in 90 per cent of the positive isolates. Most (91%) of the isolates positive for bla_CTX-M were sensitive to meropenem.

Interpretation & conclusions:

Our findings showed bla_CTX-M-15 to be the dominant gene. Based on the data on antimicrobial susceptibility, cefoperazone-sulbactum could be an antimicrobial of choice.

Analysis of Clinical Isolates of Extended-Spectrum β-Lactamase-Producing Bacteria with Primer and Probe Sets Developed to Detect blaCTX-M, blaTEM, and blaSHV Using a Fully Automated Gene Detection System

In this study, we evaluated extended-spectrum β-lactamase (ESBL)-producing bacteria with the newly developed primer and probe sets to detect bla_CTX-M, bla_TEM, and bla_SHV using BD MAX^TM, a fully automated multiplex polymerase chain reaction assay system. In 36 isolates confirmed by whole-genome sequencing to have bla_CTX-M, bla_TEM, or bla_SHV, the developed primer and probe sets accurately detected each gene without being influenced by the presence of other β-lactamase genes. In nine control strains that do not harbor either bla_CTX-M, bla_TEM, or bla_SHV no cross-reaction was observed. In 191 strains phenotypically determined to be ESBL-producers by conventional antimicrobial susceptibility tests, 189 strains were blaC_TX-M-, bla_TEM-, or bla_SHV-positive as assessed by BD MAX^TM using the developed primer and probe sets, and two strains were negative for these genes. Whole-genome sequencing revealed that these two strains were phenotypically false-positive ESBL-producers. The accuracy of the primer and probe sets seems to be satisfactory, and they may be applicable to detect CTX-M-type ESBL-producing bacteria.

High prevalence of CTX-M-1 group in ESBL-producing enterobacteriaceae infection in intensive care units in southern Chile

Enterobacteria-producing extended-spectrum β-lactamases (ESBL) play an important role in healthcare infections, increasing hospitalization time, morbidity and mortality rates. Among several ESBLs that emerge from these pathogens, CTX-M-type enzymes had the most successful global spread in different epidemiological settings. Latin America presents high prevalence of CTX-M-2 in ESBL-producing enterobacterial infections with local emergence of the CTX-M-1 group. However, this high prevalence of the CTX-M-1 group has not yet been reported in Chile. The aim of this study was to identify ESBLs among enterobacteria isolated from clinical samples of critically ill patients from southern Chile. One-hundred thirty seven ESBL-producing bacteria were isolated from outpatients from all critical patient units from Hernán Henríquez Aravena Hospital. Phenotype characterization was performed by antibiogram, screening of ESBL, and determination of minimum inhibitory concentration (MIC). PCR was used for genetic confirmation of resistance. Molecular typing was performed by ERIC-PCR. ESBL-producing isolates were identified as Klebsiella pneumoniae (n = 115), Escherichia coli (n = 18), Proteus mirabilis (n = 3), and Enterobacter cloacae (n = 1), presenting multidrug resistance profiles. PCR amplification showed that the strains were positive for blaSHV (n = 111/81%), blaCTX-M-1 (n = 116/84.7%), blaTEM (n = 100/73%), blaCTX-M-2 (n = 28/20.4%), blaCTX-M-9 (0.7%), blaPER-1 (0.7%), and blaGES-10 (0.7%). The multiple production of ESBL was observed in 93% of isolates, suggesting high genetic mobility independent of the clonal relationship. The high frequency of the CTX-M-1 group and a high rate of ESBL co-production are changing the epidemiology of the ESBL profile in Chilean intensive care units. This epidemiology is a constant and increasing challenge, not only in Chile, but worldwide.

Ugly bugs in healthy guts! Carriage of multidrug-resistant and ESBL-producing commensal Enterobacteriaceae in the intestine of healthy Nepalese adults

Background

Fecal carriage of multidrug-resistant and extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is one of the important risk factors for infection with antibiotic-resistant bacteria. In this report, we examined the prevalence of multidrug-resistant and ESBL-producing common enterobacterial strains colonizing the intestinal tract of apparently healthy adults in Kathmandu, Nepal.

Methods

During a 6-month period (February-July 2016), a total of 510 stool specimens were obtained from apparently healthy students of Manmohan Memorial Institute of Health Sciences, Kathmandu, Nepal. Stool specimens were cultured, and the most common enterobacterial isolates (Escherichia coli and Klebsiella species) were subjected to antimicrobial susceptibility tests according to the standard microbiologic guidelines. Multidrug-resistant isolates were selected for ESBL confirmation by combined disk test and E-test methods. Molecular characterization of plasmid-borne ESBL genes was performed by using specific primers of cefotaximase Munich (CTX-M), sulfhydryl variant (SHV), and temoniera (TEM) by polymerase chain reaction.

Results

Among 510 bacterial strains, E. coli (432, 84.71%) was the predominant organism followed by Klebsiella oxytoca (48, 9.41%) and K. pneumoniae (30, 5.88%). ESBLs were isolated in 9.8% of the total isolates including K. oxytoca (29.17%), E. coli (7.87%), and K. pneumoniae (6.67%). Among ESBLs, bla-TEM was the predominant type (92%) followed by bla-CTX-M (60%) and bla-SHV (4%).

Conclusion

Multidrug-resistant and ESBL-producing enterobacterial commensal strains among healthy individuals are of serious concern. Persistent carriage of ESBL organisms in healthy individuals suggests the possibility of sustained ESBL carriage among the diseased and hospitalized patients. We recommend similar types of epidemiologic surveys in larger communities and in hospital settings to ascertain the extent of ESBL resistance.