Detection and genetic characterization of extended-spectrum beta-lactamases producers in a tertiary care hospital

Contribution of genetic factors towards cefotaxime and ciprofloxacin resistance development among Extended spectrum beta-lactamase producing-Quinolone resistant pathogenic Enterobacteriaceae

β-lactams and quinolones are widely utilised to treat pathogenic Enterobacterial isolates worldwide. Due to improper use of these antibiotics, both ESBL producing and quinolone resistant (ESBL-QR) pathogenic bacteria have emerged. Nature of contribution of beta-lactamase (bla)/quinolone resistant (QR) genes, efflux pumps (AcrAB-TolC) over-expression and outer membrane proteins (OMPs) /porin loss/reduction and their combinations towards development of this phenotype were explored in this study. Kirby-Bauer disc diffusion method was used for phenotypic characterization of these bacteria and minimum inhibitory concentration of cefotaxime and ciprofloxacin was determined by broth micro dilution assay. Presence of bla, QR, gyrA/B genes was examined by PCR; acrB upregulation by real-time quantitative PCR and porin loss/reduction by SDS-PAGE. Based on antibiogram, phenotypic categorization of 715 non-duplicate clinical isolates was: ESBL+QR+ (n = 265), ESBL+QR- (n = 6), ESBL-QR+ (n = 346) and ESBL-QR-(n = 11). Increased OmpF/K35 and OmpC/K36 reduction, acrB up-regulation, prevalence of bla, QR genes and gyrA/B mutation was observed among the groups in following order: ESBL+QR+> ESBL-QR+> ESBL+QR-> ESBL-QR-. Presence of bla gene alone or combined porin loss and efflux pump upregulation or their combination contributed most for development of a highest level of cefotaxime resistance of ESBL+QR+ isolates. Similarly, combined presence of QR genes, porin loss/reduction, efflux pump upregulation and gyrA/B mutation contributed towards highest ciprofloxacin resistance development of these isolates.

Fecal carriage of extended-spectrum β-lactamase-producing enterobacterales from hospitals and community settings in Gaza Strip, Palestine

BACKGROUND

The fecal carriage of extended-spectrum β-lactamase-producing Enterobacterales (ESBL-PE) is a major driver of the global spread of these antibiotic resistance determinants. Here we determined the rate of fecal ESBL-PE carriage in pediatric hospitals and community-serving healthcare centers serving adults and children in the Gaza Strip, Palestine.

METHODS

A total of 373 fecal and rectal samples were collected from different hospitals and clinics in Gaza. The antibiotic susceptibility was determined using the disk diffusion method and interpreted according to CLSI guidelines. The bacterial isolates were tested for ESBL production using phenotypic methods (double disk synergy test and growth on selective chromogenic media). BlaCTX-M, blaSHV, and blaTEM genes were sought by PCR.

RESULTS

Out of the 373 isolates tested, 138 (37%) were considered ESBL positive as revealed by phenotypic tests. The prevalence of ESBLs among hospitalized patients was 39.1% (hospital setting) whereas, among outpatients attending community healthcare centers, it was 35.1% (community setting). ESBL production among Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Proteus mirabilis, and Klebsiella aerogenes isolates was 52.8%, 39.1%, 26.7%, 2.8%, and 2.1% respectively. Meropenem and amikacin were the most effective antibiotics against ESBL producers (68.9% and 73.6% susceptibility, respectively), while only 15.2%, 22.5%, and 24.6% remained susceptible to ceftazidime, cefotaxime, and ceftriaxone, respectively. Out of 138 phenotypically ESBL-positive isolates, 98 randomly chosen were screened for blaCTX-M, blaTEM, and blaSHV genes. The prevalence rate of blaCTX-M was 45.9%, while blaTEM and blaSHV genes were detected in 16.8% and 5.2% of CTX-M-negative isolates (corresponding mostly for K. pneumoniae isolates in the case of SHV-PCR), respectively.

CONCLUSIONS

The study revealed an alarmingly high prevalence of fecal carriage of ESBL-producing Enterobacterales among hospitalized children but also in the community of the Gaza Strip. In addition, 30% of ESBL-producers were already resistant to carbapenems, the treatment of choice of infections with ESBL-producers.

Molecular detection of plasmid mediated blaTEM, blaCTX-M,and blaSHV genes in Extended Spectrum β-Lactamase (ESBL) Escherichia coli from clinical samples

BACKGROUND

Extended spectrum β-lactamases (ESBLs) are a group of beta-lactamase enzymes that confer resistance to the oxyimino-cephalosporins and monobactams. The emergence of ESBL - producing genes possesses a serious threat for treating infections since it is associated with multi-drug resistance. This study was focused to identify the ESBLs producing genes from Escherichia coli isolates from clinical samples from a referral-level tertiary care hospital in Lalitpur.

METHODS

This was a cross-sectional study conducted from September 2018 to April 2020 at the Microbiology Laboratory of Nepal Mediciti Hospital. Clinical samples were processed, and culture isolates were identified and characterized following standard microbiological techniques. An antibiotic susceptibility test was performed by a modified Kirby-Bauer disc diffusion method as recommended by Clinical and Laboratory Standard Institute guidelines.Extended -spectrum beta-lactamases were phenotypically confirmed by the combined disc method. The ESBL-producing genes bla_TEM, bla_CTX-M and bla_SHV were confirmed by PCR.

RESULTS

Of the 1449 total E. coli isolates, 22.29% (323/1449) isolates were multi-drug resistant (MDR). Among the total MDR E. coli isolates, 66.56% (215/323) were ESBL producers. The maximum number of ESBL E. coli was isolated from urine 90.23% (194) followed by sputum 5.58% (12), swab 2.32% (5), pus 0.93% (2), and blood 0.93% (2). The antibiotic susceptibility pattern of ESBL E. coli producers showed the highest sensitivity toward tigecycline (100%) followed by polymyxin b, colistin and meropenem. Out of 215 phenotypically confirmed ESBL E. coli, only 86.51% (186) isolates were found to be positive by PCR for either bla_TEM or bla_CTX-M genes. Among the ESBL genotypes, the most common were bla_TEM 63.4% (118) followed by bla_CTX-M 36.6% (68).

CONCLUSION

The emergence of MDR and ESBL - producing E. coli isolates with high antibiotic - resistant rates to commonly used antibiotics and increased predominance of major gene types bla_TEM is a serious concern to the clinicians and microbiologists. Periodic monitoring of antibiotic susceptibility and associated genes would help guide the rationale use of antibiotics for treating the predominant pathogen E. coli in the hospitals and healthcare facilities of the communities.

Drug resistance and susceptibility of amikacin in children with extended-spectrum beta-lactamase-producing Enterobacterales: a systematic review with meta-analysis

Antibiotic resistance surveillance may be essential to identify patterns of antibiotic resistance and guide treatment choices. Therefore, this systematic review and meta-analysis aimed to evaluate amikacin resistance and susceptibility in children with extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE). From inception to September 5, 2022, relevant studies were searched via PubMed, Embase, Cochrane Library, and Web of Science databases. A network meta-analysis was conducted to explore the sequencing of resistance rates in amikacin and other antibiotics. Totally, 26 studies with 2582 clusters of bacterial isolates were included. The resistance rate of amikacin in children with ESBL-PE was 10.1%, higher than the resistance rate of tigecycline (0.0%), ertapenem (0.4%), meropenem (0.7%), and imipenem (3.0%). For the drug susceptibility rate in children with ESBL-PE, the susceptibility rate of amikacin (89.7%) was lower than tigecycline (99.6%), imipenem (96.8%), meropenem (97.3%), and ertapenem (95.6%). Amikacin showed a low drug resistance and a high drug resistance in children with ESBL-PE infection, making it a good option for the treatment of the infection caused by ESBL-PE.

Detection of extended spectrum beta-lactamase genes in Pseudomonas aeruginosa isolated from patients in rural Eastern Cape Province, South Africa

The proliferation of extended spectrum beta-lactamase (ESBL) producing Pseudomonas aeruginosa represent a major public health threat. In this study, we evaluated the antimicrobial resistance patterns of P. aeruginosa strains and characterized the ESBLs and Metallo- β-lactamases (MBL) produced. Strains of P. aeruginosa cultured from patients who attended Nelson Mandela Academic Hospital and other clinics in the four district municipalities of the Eastern Cape between August 2017 and May 2019 were identified; antimicrobial susceptibility testing was carried out against thirteen clinically relevant antibiotics using the BioMérieux VITEK 2 and confirmed by Beckman autoSCAN-4 System. Real-time PCR was done using Roche Light Cycler 2.0 to detect the presence of ESBLs; bla_SHV, bla_TEM and bla_CTX-M genes; and MBLs; bla_IMP, bla_VIM. Strains of P. aeruginosa demonstrated resistance to wide-ranging clinically relevant antibiotics including piperacillin (64.2%), followed by aztreonam (57.8%), cefepime (51.5%), ceftazidime (51.0%), piperacillin/tazobactam (50.5%), and imipenem (46.6%). A total of 75 (36.8%) multidrug-resistant (MDR) strains were observed of the total pool of isolates. The bla_TEM, bla_SHV and bla_CTX-M was detected in 79.3%, 69.5% and 31.7% isolates (n = 82), respectively. The bla_IMP was detected in 1.25% while no bla_VIM was detected in any of the strains tested. The study showed a high rate of MDR P. aeruginosa in our setting. The vast majority of these resistant strains carried bla_TEM and bla_SHV genes. Continuous monitoring of antimicrobial resistance and strict compliance towards infection prevention and control practices are the best defence against spread of MDR P. aeruginosa.