Determination of extended-spectrum ß-lactamase-producing Klebsiella pneumoniae isolated from horses with respiratory manifestation.

Background and Aim: The World Health Organization considers multidrug-resistant (MDR) Klebsiella pneumoniae a major global threat. Horses harbor commensal isolates of this bacterial species and potentially serve as reservoirs for human MDR bacteria. This study investigated antimicrobial resistance in horses caused by extended-spectrum ß-lactamase (ESBL)-producing K. pneumoniae. Materials and Methods: One hundred fifty-nine nasal swab samples were collected from horses with respiratory distress not treated with cefotaxime and erythromycin. Biochemical and serological identification was performed on all samples. Polymerase chain reaction (PCR) was used to detect 16S-23S ITS, mucoviscosity-associated gene (magA), uridine diphosphate galacturonate 4-epimerase gene (uge), and iron uptake system gene (kfu), bla TEM, bla SHV, and bla CTX genes. Sequence analysis and phylogenetic relatedness of randomly selected K. pneumoniae isolates carrying the bla TEM gene were performed. Results: Ten isolates of Klebsiella spp. were obtained from 159 samples, with an incidence of 6.28% (10 of 159). Based on biochemical and serological identification, K. pneumoniae was detected in 4.4% (7 of 159) of the samples. Using PCR, all tested K. pneumoniae isolates (n=7) carried the 16S-23S ITS gene. By contrast, no isolates carried magA, uge, and kfu genes. The bla TEM gene was detected in all test isolates. Moreover, all isolates did not harbor the bla SHV or bla CTX gene. Sequence analysis and phylogenetic relatedness reported that the maximum likelihood unrooted tree generated indicated the clustering of the test isolate with the other Gram-negative isolate bla TEM. Finally, the sequence distance of the bla TEM gene of the test isolate (generated by Lasergene) showed an identity range of 98.4-100% with the bla TEM gene of the different test isolates. Conclusion: The misuse of antimicrobials and insufficient veterinary services might help generate a population of ESBL-producing K. pneumoniae in equines and humans, representing a public health risk.

Evaluation of specific and non-specific immune response of four vaccines for caseous lymphadenitis in sheep challenged.

BACKGROUND: Caseous lymphadenitis (CLA) is a serious disease affects sheep and goat, caused by Corynebacterium pseudotuberculosis. Due to it is non-treatable disease, so the effective preventive vaccines are considered a significant way to combat the disease. All strains of C. pseudotuberculosis have several virulence factors that associated with their cell invasion, survival, and proliferation such as phospholipase D (PLD), outer lipid coat, and secreted proteases. AIM: The present study was directed to perform a comparative innate and acquired immune response assessment of different four vaccine formulas to evoke protection against induced (CLA) challenge in sheep. MATERIALS AND METHODS: Negative ELISA (free of CLA) 15 local breed male (Balady) sheep were divided into five groups, each has received a different vaccine while the control has received saline buffer. The first vaccine composed of toxoid PLD alone the second composed of toxoid PLD with bacterin (formalinkilled bacteria), the third vaccine composed of toxoid PLD plus covaccine 8, while the fourth one composed of toxoid PLD plus locally produced polyvalent clostridial vaccine. The specific immune response was evaluated through lymphocyte proliferation assay using ELISA BrdU kit, while the non-specific response was estimated by superoxide anion production and lysozyme activity assays. RESULTS: The study revealed that PLD toxoid could evoke the highest specific immune response, showing a stimulation index (9.12%). On the other hand, combined toxoid ↱PLD with bacterin followed by PLD toxoid showed a significant increase in the non-specific innate immune response. CONCLUSION: The present study indicated that the toxoid PLD alone vaccine was most efficient and provided innate and acquired immune response in animals against CLA.

Detection of Staphylococcus aureus enterotoxigenic strains in bovine raw milk by reversed passive latex agglutination and multiplex polymerase chain reaction.

AIM: This review gives an outline of the assessment of enterotoxigenic Staphylococcus aureus tainting levels in raw milk from different sources in Egypt and characterization of enterotoxigenic strains utilizing a technique in light of PCR to identify genes coding for the production of staphylococcal enterotoxin (SE). The obtained data were compared with results from the application of the reversed passive latex. MATERIALS AND METHODS: Multiplex PCR and reversed passive latex agglutination (RPLA) were used. A total of 141 samples of raw milk (cow's milk=33, buffalo's milk=58, and bulk tank milk=50) were investigated for S. aureus contamination and tested for enterotoxin genes presence and toxin production. RESULTS: S. aureus was detected in 23 (16.3%) samples phenotypically and genotypically by amplification of nuc gene. The S. aureus isolates were investigated for SEs genes (sea to see) by multiplex PCR and the toxin production by these isolates was screened by RPLA. SEs genes were detected in six isolates (26.1%) molecularly; see was the most observed gene where detected in all isolates, two isolates harbored seb, and two isolates harbored sec. According to RPLA, three isolates produced SEB and SEC. CONCLUSION: The study revealed the widespread of S. aureus strains caring genes coding for toxins. The real significance of the presence of these strains or its toxins in raw milk and their possible impact a potential hazard for staphylococcal food poisoning by raw milk consumption. Therefore, detection of enterotoxigenic S. aureus strains in raw milk is necessary for consumer safety.