Detection of Klebsiella pneumonia DNA and ESBL positive strains by PCR-based CRISPR-LbCas12a system

INTRODUCTION

Klebsiella pneumonia (K. pneumonia) is a Gram-negative bacterium that opportunistically causes nosocomial infections in the lung, bloodstream, and urinary tract. Extended-spectrum β-Lactamases (ESBLs)-expressed K. pneumonia strains are widely reported to cause antibiotic resistance and therapy failure. Therefore, early identification of K. pneumonia, especially ESBL-positive strains, is essential in preventing severe infections. However, clinical detection of K. pneumonia requires a time-consuming process in agar disk diffusion. Nucleic acid detection, like qPCR, is precise but requires expensive equipment. Recent research reveals that collateral cleavage activity of CRISPR-LbCas12a has been applied in nucleic acid detection, and the unique testing model can accommodate various testing models.

METHODS

This study established a system that combined PCR with CRISPR-LbCas12a targeting the K. pneumoniae system. Additionally, this study summarized the antibiotic-resistant information of the past five years' K. pneumoniae clinic cases in Luohu Hospital and found that the ESBL-positive strains were growing. This study then designs a crRNA that targets SHV to detect ESBL-resistant K. pneumoniae. This work is to detect K. pneumoniae and ESBL-positive strains' nucleic acid using CRISPR-Cas12 technology. We compared PCR-LbCas12 workflow with PCR and qPCR techniques.

RESULTS AND DISCUSSION

This system showed excellent detection specificity and sensitivity in both bench work and clinical samples. Due to its advantages, its application can meet different detection requirements in health centers where qPCR is not accessible. The antibiotic-resistant information is valuable for further research.

Extended-spectrum ß-lactamase-producing Escherichia coli among humans, chickens and poultry environments in Abuja, Nigeria

BACKGROUND

Globally, chicken is known to be a reservoir for the spread of antimicrobial resistance genes to humans. In Nigeria, antimicrobial drugs are readily accessible for use in poultry production, either for preventive or therapeutic purposes. Extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) are transmissible to humans because of their zoonotic potentials. People working very closely with chickens either on farms or markets are at greater risk. The aim of this study was to investigate the prevalence and zoonotic transmission of ESBL-EC among poultry-workers, chickens, and poultry environments in Abuja, Nigeria.

METHODS

We conducted a cross-sectional study among workers, chickens and poultry environment in selected farms/chicken markets in Abuja. Stool, faecal, and environmental samples were collected from apparently healthy workers, chickens, and farm/market environments from December 2018 to April 2019. Data were collected electronically using an open data kit (ODK) installed on a Smartphone. Antimicrobial resistance was determined using broth micro-dilution methods against a panel of 14 antimicrobial agents. We carried out the phenotypic and genotypic characterization of the isolates. Data were analyzed by computing frequencies, proportions and spearman's correlation (ρ).

RESULTS

Of 429 samples, 26.8% (n = 115) were positive for Escherichia coli (E. coli). Of the 115 E. coli isolates, 32.2% (n = 37) were confirmed ESBL producers by phenotypic characterization. Prevalence of ESBL-EC was highest among both poultry-workers (37.8%; n = 14) and chickens (37.8%; n = 14) followed by the environment (24.3%; n = 9). Both human and chicken isolates showed similar patterns of multidrug resistance to tested antimicrobials with a positive correlation (ρ = 0.91). Among ESBL producers, we observed the dissemination of blaCTX-M (10.8%; n = 4) genes. The coexistence of blaCTX-M-15 and blaTEM-1 genes was observed in 8.1% (n = 3) of the isolates, out of which (66.7%; n = 2) were chicken isolates from the farm, while a single human isolate was from the chicken market.

CONCLUSIONS

ESBL-EC isolates were prevalent amongst apparently healthy individuals, chickens and the poultry farm/market environment in Abuja. It is important to educate healthcare workers that people in proximity with poultry are a high-risk group for faecal carriage of ESBL-EC, hence pose a higher risk to the general population for the spread of antimicrobial resistance.

Subsequent infection with extended-spectrum β-lactamase-producing Enterobacteriaceae in patients with prior infection or fecal colonization

In clinical practice, there is a growing need to assess the impact of prior colonization or infection with extended-spectrum β-lactamase-producing Enterobacteriaceae (EPE) on new EPE infections. We have investigated the frequency of, and duration to, a subsequent EPE infection in patients with prior fecal carriage or infection with EPE. Culture data for 3272 EPE-positive patients in Western Sweden during 2004-2014 were evaluated. The median follow-up time was 3.7 years. The first recorded EPE-positive fecal screen, or clinical (urine, blood) culture, and subsequent EPE-positive clinical samples were analyzed, focusing on the first and last recurrence of EPE infection. ESBL Escherichia coli dominated (95%). Almost all (94%) patients initially positive in fecal screen (n = 1436) and 72 and 71% of those initially positive in urine (n = 1717) and blood (n = 119) had no further EPE clinical isolates. Subsequent EPE bacteremia was only detected in 0.7, 1.6, and 4.2% of the respective patient group. Recurrent EPE-positive urine cultures occurred in 27% (460/1717), most (75%) within 6 months, and rarely (13%) after 1 year. Repeated EPE-positive clinical samples were significantly (p < 0.01) more common in patients > 65 years and in men with ESBL Klebsiella pneumoniae. In our low-endemic setting, subsequent EPE infections in previously colonized patients were rare. On the other hand, in patients previously EPE-positive in urine or blood, subsequent EPE urinary tract infections were common, especially within 6 months and in patients > 65 years old.

Extended-spectrum β-lactamases producing Klebsiella pneumoniae isolated in two hospitals in Goiânia/Brazil: detection, prevalence, antimicrobial susceptibility and molecular typing

This study was developed to evaluate the prevalence of extended-spectrum β-lactamases (ESBL) producing Klebsiella pneumoniae in two hospitals (A and B) in Goiânia, GO, Brazil. The antimicrobial susceptibility of the isolates was determined using the MicroScan WalkAway (Dade Behring, USA). Tests to evaluate the genetic correlation between the isolates were also performed. For the ESBL phenotypic test, the Double-disk diffusion (DD) method was used. The strains isolated in Hospital B were submitted to DNA analysis by pulsed-field gel electrophoresis (PFGE). The study showed high prevalence of ESBL-producing K. pneumoniae (25% in hospital A and 66.7% in hospital B), with high rates of antimicrobial resistance. The most active compound was imipenem (100% susceptibility in vitro). The PFGE test showed similiarity in five strains and variability in six strains.The high prevalence of ESBL-producing Klebsiella may be due to individual selection and to dissemination of a common strain.