Laboratory Detection and Neutralizing Activity of Exocellular AmpC β-lactamases by Anti bla-CMY

Detection of AmpC β-lactamases (AmpC-bls) is important for infection control purposes and therapeutic options. Here, we provided a diagnostic anti β-lactamase neutralization test (bla-NT); modified from broth microdilution (BM) for the detection of bls-AmpC, CMY, in multidrug resistant Escherichia coli and Klebsiella pneumoniae. Anti-bla neutralizing activity against these two bacteria was tested. Anti bla-CMY was prepared in rabbits and used in: bla-NT; investigating effect on bacterial colony forming unit (CFU); and in ELISA. In bla-NT, the anti-bla-CMY neutralized exocellular bls produced by the tested bacterial strains and resulted in an increase in the bacterial sensitivity to the tested antimicrobials and reduction in minimum inhibitory concentration. Interestingly, the anti-bla-CMY decreased the CFU and its morphology when added to the tested bacteria. ELISA-OD was significantly correlated with the drop in minimum inhibitory concentration and CFU counts at P-value ≤ 0.05 and 0.01, respectively. It could be concluded that, bla-NT could detect bls-AmpC and run parallel to BM in microbiology laboratory. Investigations are running to develop the test for quantitative detection of bls-AmpC

Prevalence of plasmid-mediated AmpC in Enterobacteriaceae isolated from humans and from retail meat in Zagazig, Egypt

Abstract Background The objective of this study was to determine the prevalence of plasmid-mediated AmpC (pAmpC) among Enterobacteriaceae isolated from humans and from retail meat in Egypt. Methods Enterobacteriaceae were isolated from patients with suspected bloodstream infection, human fecal samples, retail chicken meat samples and retail sheep meat samples. All group I Enterobacteriaceae were analyzed for presence of pAmpC genes by PCR. Antibiotic susceptibility testing was performed in all pAmpC positive isolates, followed by phenotypic and genotypic ESBL and carbapenemase testing on indication. Results The prevalence of pAmpC among group I Enterobacteriaceae isolated from 225 patients with bloodstream infection was 5.6% [95%CI 2.2–13.4]. Among 100 patients with community-onset gastroenteritis the prevalence in fecal samples was 4.8% [95%CI 2.1–10.7]. The prevalence among 112 chicken carcasses and 100 sheep meat samples was 2.4% [95%CI 0.7–8.4] and 1.1% [95%CI 0.2–5.7], respectively. In half of the AmpC positive isolates we detected an ESBL gene and 2 isolates harbored a carbapenemase gene. In five isolates there was resistance to at least three important alternative antibiotic drugs. Conclusions We consider the prevalence of pAmpC in Egypt, as found in our study, moderately low. To follow future trends in prevalence of pAmpC worldwide, a standardized screening algorithm for the detection of pAmpC is needed

<i>Nigella sativa</i> Extract Potentially Inhibited Methicillin Resistant <i>Staphylococcus aureus</i> Induced Infection in Rabbits: Potential Immunomodulatory and Growth Promoting Properties

Weaning is the most crucial period associated with increased stress and susceptibility to diseases in rabbits. Methicillin-resistant Staphylococcus aureus (MRSA), a historic emergent pathogen related to post weaning stressors, adversely affects rabbit’s growth rate and productive cycle. Since MRSA is rapidly evolving antibiotics resistance, natural products are desperately required to tackle the public health threats posed by antimicrobial resistance. Thus, this study aimed to screen the iin vitro antibacterial activity of Nigella sativa extract (NSE) and its interactions with antibiotics against MRSA isolates. Moreover, 200 weaned rabbits were divided into 4 groups to investigate the iin vivo superiority of NSE graded levels towards growth performance, tight junction integrity, immune responsiveness and resistance against MRSA. Herein, NSE showed promising antimicrobial activities against MRSA isolates from animal (77.8%) and human (64.3%) origins. Additionally, MRSA isolates exposed to NSE became sensitive to all antimicrobials to which they were previously resistant. Our results described that the growth-promoting functions of NSE, especially at higher levels, were supported by elevated activities of digestive linked enzymes. Post-NSE feeding, rabbits’ sera mediated bactericidal activities against MRSA. Notably, upregulated expression of occludin, CLDN-1, MUC-2 and JAM-2 genes was noted post NSE supplementation with maximum transcriptional levels in 500 mg/kg NSE fed group. Our data described that NSE constitutively motivated rabbits’ immune responses and protected them against MRSA-induced experimental infection. Our results suggest the antimicrobial, growth stimulating and immunomodulation activities of NSE to maximize the capability of rabbits for disease response