[Epidemiological and etiological analysis of two infantile cases of serogroup B epidemic cerebrospinal meningitis epidemics in Shandong Province, 2021].

Two cases of epidemic situation of serogroup B meningitis in infants in Shandong Province in 2021 were investigated. Samples of cases and their close contacts were collected for isolation, culture and identification of Neisseria meningitides (Nm). The isolates were subjected to multi-locus sequence typing, outer membrane protein porA and fetA genotyping and drug sensitivity test. Two laboratory-confirmed outbreaks of serogroup B meningitis were reported from Yantai city and Linyi city. The indicated cases were infants aged 5 months and 2 months old respectively. They were not vaccinated with meningitis vaccine. Their epidemiological characteristics and clinical manifestations were similar and the prognosis was good. The same sequence type (ST) of serogroup B Nm strains as the indicated cases was detected in the samples of close family contacts, but without subsequent cases. Among them, Yantai strain was were identified as the type ST-8920, belonging to CC4821 clonal complex, and the genotypes of porA and fetA were p1.21-2, 23 and F3-1. Linyi strain was a new type, belonging to CC4821 clonal complex and the genotypes of porA and fetA were p1.20, 23 and F1-91. The above strains were resistant to penicillin, ciprofloxacin, levofloxacin and Chemitrim, and their sensitivity to cephalosporin decreased. Two cases of infant serogroup B epidemic were relatively rare in China, which were different from the epidemiological and pathogenic characteristics of other Nm serogroups in the past.

Energy, amino acid, and phosphorus digestibility of phytase transgenic corn for growing pigs.

Three experiments were conducted to evaluate energy, AA, and P digestibility in a phytase transgenic corn (PTC) containing a phytase gene (phyA2) isolated from Aspergillus niger compared with a nontransgenic near-isoline conventional corn (CC) grown in the same environmental conditions for growing pigs. Experiment 1 was an energy balance experiment conducted to measure DE and ME in PTC and CC. Eighteen growing barrows (initial BW 25.8±0.3 kg) from 9 litters were allotted by BW and litter to 1 of 2 dietary treatments with 9 pigs per treatment in a randomized complete block design. Pigs were individually placed in metabolism cages and fed diets based on the 2 corns. The DE and ME in PTC (3,967 and 3,941 kcal/kg of DM, respectively) were greater (P<0.05) than those in CC (3,917 and 3,848 kcal/kg of DM, respectively). Experiment 2 was conducted to measure apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of CP and AA in the 2 corns. Eighteen growing barrows (initial BW 41.8±0.7 kg) were equipped with a T-cannula in the distal ileum. Pigs were placed in metabolism cages in a completely randomized design with 3 dietary treatments of 6 pigs each. An N-free diet was used to estimate basal endogenous losses of CP and AA. The AID and SID values for CP and all AA did not differ between the 2 corns. Experiment 3 was conducted to measure apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) values of P in the 2 corns. Eighteen growing pigs (initial BW 30.5±0.5 kg) from 6 litters were placed in metabolism cages in a randomized complete block design with 3 dietary treatments of 6 pigs each based on BW and litter. Two diets were based on the 2 corns, and a P-free diet was used to measure endogenous P losses. The ATTD and STTD values of P were greater (P<0.05) in the PTC diet (71.4% and 76.9%, respectively) than those in the CC diet (27.6% and 33.4%, respectively). Pigs fed the PTC diet had a greater (P<0.05) P retention (70.7%) than those fed the CC diet (27.1%). It was concluded that PTC had a greater digestibility of energy and P than CC for growing pigs. As a consequence, if PTC replaces CC in a pig diet, the DE and ME in the diet will increase, and less inorganic P will need to be supplemented to the diet, and thus P excretion in manure will be decreased.