Objective:To investigate the in vitro antibacterial effects of imipenem combined with common antibiotics on bla KPC-2 type carbapenem resistant klebsiella pneumoniae (CRKP) targeting bla KPC-2 gene. Methods:Six strains of unrepeated bla KPC-2 type confirmed by polymerase chain reaction and DNA sequence were isolated in Yueqing People's Hospital, China between January 2018 and January 2019 were included in this study. The susceptibility rate of imipenem against nine conventionally used antibiotics was determined. The sensitivity test of imipenem combined with eight antibiotics was performed with the checkerboard method. Fractional inhibitory concentration was calculated to assess the efficacy of imipenem combined with common antibiotics. The in vitro treatment time-antibacterial effect curve was drawn to evaluate the antibacterial effects. Results:The resistance rate of six strains of bla KPC-2 type was 100.00% (6/6) for imipenem, meropenem, ceftazidime, ciprofloxacin, rifampicin and cefotaxime, and it was 66.67% (4/6) for minocycline and clavulanic acid and 33.33% (2/6) for tigecycline. Imipenem combined with tigecycline had a better antibacterial effect and exhibited a synergistic effect on four strains of bla KPC-2 type CRKP and an additive effect on two strains of Bla KPC-2 type CRKP. The curve of time for in vitro treatment of KPN2 with imipenem combined with tigecycline against bactericidal effect revealed that the antibacterial rate of imipenem at the 1/2 minimum inhibitory concentration combined with tigecycline at the 1/4 minimum inhibitory concentration was > 95% at (t+2) and the antibacterial effect could maintain (t+10) hours to (t+12) hours. The antibacterial rate of imipenem combined with tigecycline against strain 002 was gradually decreased with time, and the growth curve of strain 002 rised gradually. Conclusion:In vitro drug sensitivity test revealed that imipenem combined with tigecycline exhibits a good synergistic effect on bla KPC-2 type CRKP. Findings from this study provide a reference for clinical treatment of bla KPC-2 type CRKP.

OBJECTIVETo assess the levels of polycyclic aromatic hydrocarbons monohydroxy metabolites in urine of general population in China among 8 provinces, provide the baseline of the metabolites in the general population.

METHODSFrom 2009 to 2010, 18 120 subjects of general population aged 6-60 years old were recruited from 24 areas among 8 provinces in east, west and central areas of China mainland by cluster random sampling. The information of the living environment and health condition were collected by questionnaire and spot urine samples were collected, 4 680 urine samples were analysed by high performance liquid chromatography with tandem mass spectrometry, and monohydroxy metabolites distribution in urine among groups of gender and ages were analysed.

RESULTSGeometric means (GM) of 2-naphthol, 1-naphthol, 3-phenanthrol and 1-hydroxypyrene concentration in urine (95%CI) were 1.85 (1.75-1.95), 1.55 (1.50-1.61), 0.57 (0.54-0.59) and 0.82 (0.78-0.85) µg/L, respectively;and median are 2.44, <0.50, 0.72 and 0.90 µg/L, respectively. The concentration between male and female were significantly different (P < 0.01), and the concentration among the groups of population were significantly different (P < 0.01), the GM of 2-naphthol among the groups of population aged 6-12, 13-16, 17-20, 21-30, 31-45 and 46-60 years old were 1.60, 1.56, 1.69, 2.23, 1.91 and 1.86 µg/L (χ(2) = 17.90, P < 0.01), the GM of 1-naphthol in the groups were 1.30, 1.16, 1.53, 1.68, 1.80 and 1.52 µg/L (χ(2) = 76.22, P < 0.01), the GM of 3-phenanthrol in the groups were 0.78, 0.76, 0.55, 0.42, 0.50 and 0.99 µg/L (χ(2) = 66.48, P < 0.01), the GM of 1-hydroxypyrene in the groups were 0.77,0.64, 1.00, 0.84, 0.84 and 0.57 µg/L (χ(2) = 51.48, P < 0.01), respectively.

CONCLUSIONThe distribution of monohydroxy metabolites levels in urine of general population were different, it provided a basic data for the further study of polycyclic aromatic hydrocarbons biomonitoring in the population.

Adolescent ; Adult ; Child ; China ; epidemiology ; Cross-Sectional Studies ; Environmental Exposure ; Female ; Humans ; Male ; Middle Aged ; Naphthols ; urine ; Polycyclic Aromatic Hydrocarbons ; urine ; Pyrenes ; urine ; Sentinel Surveillance ; Young Adult