Cross-Resistance and the Mechanisms of Cephalosporin-Resistant Bacteria in Urinary Tract Infections Isolated in Indonesia

Application of phylodynamics to identify spread of antimicrobial-resistant Escherichia coli between humans and canines in an urban environment

The transmission of antimicrobial resistant bacteria in the urban environment is poorly understood. We utilized genomic sequencing and phylogenetics to characterize the transmission dynamics of antimicrobial resistant Escherichia coli (AMR-Ec) cultured from putative canine (caninep) and human feces present on urban sidewalks in San Francisco, California. We isolated a total of fifty-six AMR-Ec isolates from human (n = 20) and caninep (n = 36) fecal samples from the Tenderloin and South of Market (SoMa) neighborhoods of San Francisco. We then analyzed phenotypic and genotypic antimicrobial resistance (AMR) of the isolates, as well as clonal relationships based on cgMLST and single nucleotide polymorphisms (SNPs) of the core genomes. Using Bayesian inference, we reconstructed the transmission dynamics between humans and caninesp from multiple local outbreak clusters using the marginal structured coalescent approximation (MASCOT). Our results provide evidence for multiple sharing events of AMR-Ec between humans and caninesp. In particular, we found one instance of likely transmission from caninesp to humans as well as an additional local outbreak cluster consisting of one caninep and one human sample. Based on this analysis, it appears that non-human feces act as an important reservoir of clinically relevant AMR-Ec within the urban environment for this study population. This work showcases the utility of genomic epidemiology to reconstruct potential pathways by which antimicrobial resistance spreads.

Antibiotic Resistance in Proteus mirabilis: Mechanism, Status, and Public Health Significance

Proteus mirabilis is a specific opportunistic pathogen of many infections including urinary tract infections (UTIs). Risk factors are linked with the acquisition of multidrug-resistant (MDR) to 3 or more classes of antimicrobials) strains. The resistance in extended-spectrum alpha-lactamase is rare, but the rising resistance in extended-spectrum beta-lactamase (ESBL) producing strains is a matter of concern. β-lactamases and antibiotic modifying enzymes mainly constitute the ESBLs resistance mechanism by hydrolyzing the antibiotics. Mutation or Porin loss could lead to the reduced permeability of antibiotics, enhanced efflux pump activity hindering the antibiotic access to the target site, antibiotic failure to bind at the target site because of the target modification, and lipopolysaccharide mutation causing the resistance against polymyxin antibiotics. This review aimed to explore various antimicrobial resistance mechanisms in Proteus mirabilis and their impact on public health status.

Impact on quinolone resistance of plasmid-mediated quinolone resistance gene and mutations in quinolone resistance-determining regions in extended spectrum beta lactamase-producing Klebsiella pneumoniae isolated from urinary tract infection patients

Klebsiella pneumoniae is a typical pathogen in urinary tract infections (UTI), and the emergence of extended spectrum beta-lactamase (ESBL)-producing strains has been frequently reported, accompanied by higher quinolone resistance rates. There are two major mechanisms of quinolone resistance, mutations in quinolone resistance-determining regions (QRDR) and the presence of the plasmid-mediated quinolone resistance (PMQR) genes. This study aimed to investigate quinolone resistance among 105 ESBL-producing K. pneumoniae specimens isolated from UTI patients in Indonesia. These were characterized for antimicrobial resistance to nalidixic acid, ciprofloxacin and levofloxacin, QRDR mutations in gyrA and parC and the presence of PMQR genes. We found that 84.8% of the collected isolates were resistant to at least one of the quinolones. QRDR mutation in gyrA was observed in 49.5% of these strains and parC mutations in 61.0%. PMQR genes were identified in 84.8% of strains. The QRDR mutations clearly had a greater effect on resistance than the PMQR genes. In conclusion, we found high quinolone resistance rates in Indonesian ESBL-producing K. pneumoniae, in which QRDR mutation played a major role.

Multidrug-Resistant Klebsiella pneumoniae Causing Severe Infections in the Neuro-ICU

The purpose of this study was the identification of genetic lineages and antimicrobial resistance (AMR) and virulence genes in Klebsiella pneumoniae isolates associated with severe infections in the neuro-ICU. Susceptibility to antimicrobials was determined using the Vitek-2 instrument. AMR and virulence genes, sequence types (STs), and capsular types were identified by PCR. Whole-genome sequencing was conducted on the Illumina MiSeq platform. It was shown that K. pneumoniae isolates of ST14^K2, ST23^K57, ST39^K23, ST76^K23, ST86^K2, ST218^K57, ST219^KL125/114, ST268^K20, and ST2674^K47 caused severe systemic infections, including ST14^K2, ST39^K23, and ST268^K20 that were associated with fatal incomes. Moreover, eight isolates of ST395^K2 and ST307^{KL102/149/155} were associated with manifestations of vasculitis and microcirculation disorders. Another 12 K. pneumoniae isolates of ST395^K2,KL39, ST307^{KL102/149/155}, and ST147^K14/64 were collected from patients without severe systemic infections. Major isolates (n = 38) were XDR and MDR. Beta-lactamase genes were identified: bla_SHV (n = 41), bla_CTX-M (n = 28), bla_TEM (n = 21), bla_OXA-48 (n = 21), bla_NDM (n = 1), and bla_KPC (n = 1). The prevalent virulence genes were wabG (n = 41), fimH (n = 41), allS (n = 41), and uge (n = 34), and rarer, detected only in the genomes of the isolates causing severe systemic infections-rmpA (n = 8), kfu (n = 6), iroN (n = 5), and iroD (n = 5) indicating high potential of the isolates for hypervirulence.