Characterization of CTX-M-type-extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolated from Indonesian undergraduate medical students of a university in Surabaya, Indonesia

Analysis of the upstream genetic structures of the ISEcp1-blaCTX-M transposition units in Escherichia coli isolates carrying blaCTX-M obtained from the Indonesian and Vietnamese communities

Extended spectrum β-lactamase (ESBL)-producing Escherichia coli have been found in healthy individuals in Indonesia and Vietnam. The ISEcp1-bla_CTX-M transposition unit of ESBL-producing bacterial isolates has been considered responsible for the production of CTX-M type ESBL and it is important for the dissemination of bla_CTX-M . This study aimed to characterize the upstream genetic structure (UGS) of E. coli isolates possessing bla_CTX-M-1 group and/or bla_CTX-M-9 group genes obtained from healthy individuals in Indonesia and Vietnam. A total of 501 CTX-M type ESBL-producing E. coli isolates possessing bla_CTX-M-1 group and/or bla_CTX-M-9 group genes were obtained from healthy individuals of the two countries in 2018. The UGSs of the ISEcp1-bla_CTX-M transposition unit of the 501 ESBL-producing E. coli isolates were amplified by barcode-adaptor-ligation-mediated PCR and analyzed using the Nanopore sequencer. The obtained sequence information was used to classify the UGSs of the ISEcp1-bla_CTX-M transposition unit. From the 501 ESBL-producing E. coli isolates, 502 UGSs were obtained, which were classified into 85 UGS types based on the sequence. ISEcp1 of 359 (71.5%) of the 502 UGSs was disrupted by gene insertion, and ISEcp1-bla_CTX-M transposition unit of most (87.1%) of the determined UGSs was confirmed as plasmidic. Only 6 (7.1%) of the 85 UGS types were common to both countries. Our results indicated that many different UGSs of ISEcp1-bla_CTX-M transposition units were detected in Indonesia and Vietnam; hence, we suggest that structurally different kinds of plasmids harboring bla_CTX-M were separately distributed in the two countries.

Occurrence of Carriage of Multidrug Resistant Enterobacteriaceae among Pregnant Women in the Primary Health Center and Hospital Setting in Surabaya, Indonesia

Objectives: The incidence of healthy individuals carrying multidrug resistant Enterobacteriaceae, including extended-spectrum β-lactamase producing Enterobacteriaceae (ESBL-E), especially extended-spectrum β-lactamase producing Escherichia coli (ESBL-EC) and extended-spectrum β-lactamase producing Klebsiella pneumoniae (ESBL-KP), is increasing worldwide. Although ESBL-E causes early or late onset of neonatal sepsis, the prevalence of ESBL-E carriage among pregnant women in Indonesia is not clear. In the present study, we compared the occurrence of carriage of ESBL-E among pregnant women in a primary health center (PHC) versus two hospitals. Materials and Methods: We collected rectal swab samples from 200 pregnant women who visited a PHC or were admitted to two hospitals in Surabaya, Indonesia from July to October 2018. The ESBL-E strains were isolated from the samples and phenotypically and genotypically analyzed. Results: ESBL-E strains were isolated from 25 (24.8%) pregnant women who visited the PHC and 49 (49.5%) pregnant women who were admitted to the hospitals. The rate of ESBL-E carriage of pregnant women in the hospitals was significantly higher than that in the PHC. Among the 74 isolated ESBL-E strains, ESBL-EC was most frequently isolated (62 strains), followed by ESBL-KP (12 strains). In addition, bla_CTX-M-15 was the most frequent ESBL gene type of the isolated ESBL-E strains. Conclusions: Our results revealed the high occurrence of ESBL-E carriage in pregnant women, especially those who were admitted to the hospitals.

Differential effects of chromosome and plasmid blaCTX-M-15 genes on antibiotic susceptibilities in extended-spectrum beta-lactamase-producing Escherichia coli isolates from patients with urinary tract infection

OBJECTIVES

To compare antibiotic susceptibilities between chromosomal and plasmid blaCTX-M-15 locations in urinary tract infection-causing extended-spectrum β-lactamases-producing Escherichia coli blaCTX-M-15 isolated in Indonesia.

METHODS

A total of 84 strains identified as extended-spectrum β-lactamases-producing E. coli were isolated from patients with urinary tract infection in Indonesia in 2015. Antimicrobial susceptibility tests were performed on these strains using 18 antibiotics, and extended-spectrum β-lactamase bla genes were detected by polymerase chain reaction. Gene localization of blaCTX-M-15 -positive strains was confirmed by Southern blot hybridization, and epidemiological typing was conducted using multilocus sequence typing.

RESULTS

Of 54 strains harboring the blaCTX-M-15 gene, 27 showed localization on chromosome, 20 on plasmid, and seven on chromosome and plasmid. Most multilocus sequence typing sequence types of the 27 strains with chromosomal blaCTX-M-15 were ST405 (25.9%) and ST131 (22.2%) strains, whereas the 20 strains with plasmid-blaCTX-M-15 were mostly ST410 (55.0%).

CONCLUSIONS

Extended-spectrum β-lactamases-producing E. coli blaCTX-M-15 with plasmid genes show significantly higher resistant rates against piperacillin-tazobactam but lower resistant rates against chloramphenicol compared to chromosomal strains in Indonesian patients with urinary tract infection. Mechanistic investigations will be necessary to advance our knowledge of antimicrobial resistance in urinary tract infection.

A high-throughput sequencing determination method for upstream genetic structure (UGS) of ISEcp1-blaCTX-M transposition unit and application of the UGS to classification of bacterial isolates possessing blaCTX-M

INTRODUCTION

Because bla_CTX-M is responsible for resistance of bacteria to the third generation cephalosporins, location of bla_CTX-M could be a good indicator for classifying bacterial isolates harboring bla_CTX-M in molecular epidemiology. However, determination of bla_CTX-M location has been difficult when multiple copies of ISEcp1 were found on bacterial genome. We aimed to establish a high-throughput analytical method for upstream genetic structures (UGS) of ISEcp1 to facilitate determination of bla_CTX-M location.

METHODS

Extracted DNA samples obtained from 168 Escherichia coli isolates possessing bla_CTX-M were digested by restriction enzyme, HaeIII, and the digested DNA fragments were ligated with homemade barcode adaptors. Then, DNA fragments containing UGS of ISEcp1 were amplified and subjected to the Nanopore sequencer.

RESULTS

Nucleotide sequences and locations of 168 UGSs obtained from the examined E. coli isolates were determined. Among the 168 determined UGSs, 150 (89.3%) UGS were confirmed on plasmid and classified into eight types. Interestingly, coding sequence of ISEcp1 transposase gene in seven of the eight types were disrupted by IS26 insertion. The remaining 18 (10.7%) UGSs were observed in identical chromosomal region. The obtained nucleotide sequences the locations of UGSs were confirmed by conventional capillary sequencer and Southern blotting, respectively, and any discrepant result was not observed with these confirmation procedures.

CONCLUSIONS

Our results indicated that the established method was efficient for simultaneously determining at least 100 different UGS, and suggested that the determined UGSs of ISEcp1-bla_CTX-M transposition unit was useful for classification of bacterial isolates harboring bla_CTX-M.

Clinical and computed tomography features of extended-spectrum β-lactamase-producing Klebsiella pneumoniae liver abscess

Background

Klebsiella pneumoniae (KP) is the primary pathogen associated with pyogenic liver abscesses (PLAs). Moreover, there has been an increase in the proportion of extended-spectrum beta-lactamase (ESBL)-producing KP. However, the clinical and computed tomography (CT) features of liver abscesses caused by ESBL-producing KP have not been separately described. We aimed to compare the clinical and CT features present in patients with ESBL-producing and non-ESBL-producing KP as well as to determine the risk factors for ESBL-producing KP liver abscesses (KPLAs).

Methods

We performed a retrospective analysis of data obtained from the medical records of patients with a first episode of KPLA admitted to Shengjing Hospital of China Medical University between May 2015 and May 2019. We compared the clinical and CT features between patients with ESBL-producing and non-ESBL-producing KPLA.

Results

We enrolled 100 patients with KPLA (14 and 86 in the ESBL-producing and non-ESBL-producing groups, respectively). There was no significant between-group difference in the proportion of patients with comorbid diabetes (71.43% vs. 66.2%, p = 0.086). The ESBL-producing KPLA group had a greater proportion of patients with a history of biliary disease (78.57% vs. 26.74%, p < 0.001) and gastrointestinal malignancy (50% vs. 6.98%, p < 0.001). Multivariate regression analysis showed that a history of biliary disease was an independent risk factor for ESBL-producing KPLA. Compared with the non-ESBL-producing KPLA group, the ESBL-producing KPLA group had a significantly higher intensive care unit (ICU) admission rate (28.57% vs. 2.33%, p < 0.001). All ESBL-producing KP isolates were susceptible to carbapenems and amikacin. Only the presence of multiloculation on CT was found to be significantly different between the groups (50% vs. 82.56%, p = 0.012).

Conclusions

The presence of biliary disease was an independent risk factor for ESBL-producing KPLA. Patients with ESBL-producing KPLA had a higher ICU admission rate, with only half of patients having evidence of multiloculation on CT.