Klebsiella pneumoniae is important human and animal pathogen that causes a wide spectrum of infections. In this study, isolates from cattle nasal swabs samples were identified by 16S rRNA, and to evaluate the antimicrobial susceptibility, virulence gene carrying levels, and multilocus sequence typing of K. pneumoniae isolates. 33 isolates of K. pneumoniae were isolated and identified in 213 nasal swabs samples, of which 12 were hypervirulent K. pneumoniae strains. Extended Spectrum Beta-Lactamases genes were found in 93.4% of the strains. Of which, TEM was the most prevalent (93.4%), followed by CTX-M and SHV were 57.6% and 39.4%, respectively. A main mutation pattern of quinoloneresistance-determining region, Thr83-Ieu and Asp87-Asn in gyrA and Ser87-Ile in parC, was detected in 33 K. pneumoniae isolates. All the isolates harbored at least two virulence factor genes, with ureA (97.0%) and wabG (91.0%) exhibiting high carriage rates in 33 K. pneumoniae isolates. MLST revealed 7 sequence types, of which 3 STs (2541, 2581 and 2844) were newly assigned. Using eBURST, ST2844 and ST2541 were assigned to new clonal complex 2844. Our study provides evidence and biological characteristics of K. pneumoniae isolates from cattle upper respiratory tract in Southwest China.

Fowl cholera caused by Pasteurella multocida has always been a disease of global importance for poultry production. The aim of this study was to obtain more information about the epidemiology of avian P. multocida infection in southwest China and the genetic characteristics of clinical isolates. P. multocida isolates were characterized by biochemical and molecular-biological methods. The distributions of the capsular serogroups, the phenotypic antimicrobial resistance profiles, lipopolysaccharide (LPS) genotyping and the presence of 19 virulence genes were investigated in 45 isolates of P. multocida that were associated with clinical disease in poultry. The genetic diversity of P. multocida strains was performed by 16S rRNA and rpoB gene sequence analysis as well as multilocus sequence typing (MLST). The results showed that most (80.0%) of the P. multocida isolates in this study represented special P. multocida subspecies, and 71.1% of the isolates showed multiple-drug resistance. 45 isolates belonged to capsular types: A (100%) and two LPS genotypes: L1 (95.6%) and L3 (4.4%). MLST revealed two new alleles (pmi77 and gdh57) and one new sequence type (ST342). ST129 types dominated in 45 P. multocida isolates. Isolates belonging to ST129 were with the genes ompH+plpB+ptfA+tonB, whereas ST342 included isolates with fur+hgbA+tonB genes. Population genetic analysis and the MLST results revealed that at least one new ST genotype was present in the avian P. multocida in China. These findings provide novel insights into the epidemiological characteristics of avian P. multocida isolates in southwest China.

Pasteurella multocida (P. multocida) causes fowl cholera in birds and the pathogenesis and virulence factors involved are still poorly understood. TonB protein is a periplasmic protein prevalent in a large number of Gram-negative bacteria, as in Pasteurella, which is believed to be responsible for the import of ferric iron complexes across the outer membrane and plays a role as an important virulence factor to help bacteria to obtain nutrients. In this study, a total of 23 isolates of P. multocida were obtained from 172 cases of clinical respiratory disease in duck and geese, giving an isolation rate of 13.4%. P. multocida Serogroup A was isolated from 22 cases (95.7%), whereas serogroup F was from 1 case (4.3%). All isolates were analyzed for their susceptibility to 15 antibiotics and the presence of 18 genes for virulence factors. The susceptibility profiles suggested that Tetracycline, Cephalosporin, Enrofloxacin, and Aminoglycosides were the drugs most likely to be active against P. multocida. However, 78.3% and 52.2% of poultry strains were resistant to Penicillin and Sulfisoxazole, respectively. PCR results showed that ptfA, fimA, tonB, fur, hgbA, hgbB, sodA, sodC, pmHAS, nanH, nanB, plpB and ompH genes occur in most poultry strains of P. multocida. The virulence genes such as toxA, tadD, hsf-1, pfhA and ompA were each present in <73.9% of strains. The tonB gene was detected in all 23 clinical strains of P. multocida which were recovered from different hosts and harboring different serotypes. Phylogenetic analysis indicated that these tonB genes of P. multocida from different hosts and harboring different serotypes have close genetic relationship with a high similarity. Multiple sequence alignment demonstrated that TonB protein of Gram-negative bacteria exists in multiple conserved sites, such as -xSSGx-, -YP-, -LD-and xA[A/V]Lx motif. These findings provide clinical data into the epidemiological and molecular characteristics of avian P. multocida isolates and provide a reference for the researches of drug target in P. multocida. Keywords: Antimicrobial susceptibility, Capsular antigens, Pasteurella multocida, tonB gene, Virulence gene, Cloning, Phylogenetic analysis Çin'de Kanatlı Hayvanlardan İzole Edilen Pasteurella multocida Sışlarının Moleküler Karakterizasyonu ve tonB Geni Açısından Genetik Analizi ÖzetPasteurella multocida (P. multocida) kuşlarda kanatlı kolerasına neden olur ve hastalıkta virulans faktörleri hala tam olarak anlaşılamamıştır. TonB proteini Pasteurella da dahil pek çok Gram-negatif bakteride yaygın olarak bulunan periplazmik bir protein olup membran dışına ferrik demir komplekslerini taşımakta görevlidir ve bakterilerde besin sağlamaya yardım etmek suretiyle önemli bir virulans faktörü olarak rol oynar. Bu çalışmada, 172 klinik solunum hastalıklı ördek ve kazdan toplam 23 P. multocida izolatı elde edilerek %13.4'lük izolasyon oranı sağlandı. P. multocida Serogrup A 22 vakadan izole edilirken (%95.7), serogrup F 1 vakadan izole edildi (%4.3). Tüm izolatlar 15 antibiyotiğe kar...