Characterization of Staphylococci and Streptococci Isolated from Milk of Bovides with Mastitis in Egypt.

Wedad Ahmed,Ashraf Awad Abdeltawab,Heinrich Neubauer,Helmut Hotzel,Fatma Ibrahim El Hofy,Stefan Monecke,Herbert Tomaso

doi:10.3390/pathogens9050381

Abstract

The aim of this study was to characterize staphylococci and streptococci in milk from Egyptian bovides. In total, 50 milk samples were collected from localities in the Nile Delta region of Egypt. Isolates were cultivated, identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic susceptibility testing was performed by the broth microdilution method. PCR amplifications were carried out, targeting resistance-associated genes. Thirty-eight Staphylococcus isolates and six Streptococcus isolates could be cultivated. Staphylococcus aureus isolates revealed a high resistance rate to penicillin, ampicillin, clindamycin, and erythromycin. The mecA gene defining methicillin-resistant Staphylococcus aureus, erm(C) and aac-aphD genes was found in 87.5% of each. Coagulase-negative staphylococci showed a high prevalence of mecA, blaZ and tetK genes. Other resistance-associated genes were found. All Streptococcus dysgalactiae isolates carried blaZ, erm(A), erm(B), erm(C) and lnuA genes, while Streptococcus suis harbored erm(C), aphA-3, tetL and tetM genes, additionally. In Streptococcus gallolyticus, most of these genes were found. The Streptococcus agalactiae isolate harbored blaZ, erm(B), erm(C), lnuA, tetK, tetL and tetM genes. Streptococcus agalactiae isolate was analyzed by DNA microarray analysis. It was determined as sequence type 14, belonging to clonal complex 19 and represented capsule type VI. Pilus and cell wall protein genes, pavA, cadD and emrB/qacA genes were identified by microarray analysis.

Highlights

Mastitis is an infection or inflammation of the mammary gland
38 Staphylococcus isolates were obtained from 50 milk samples of cattle and buffaloes
Identification by MALDI-TOF MS resulted in S. warneri (n = 9), S. aureus (n = 8), S. pasteuri (n = 8), S. xylosus (n = 4), S. epidermidis (n = 2), S. chromogenes (n = 2), S. cohnii (n = 1), S. hyicus (n = 1), S. haemolyticus (n = 1), S. sciuri (n = 1), S. lentus (n = 1), St. dysgalactiae (n = 3), St. agalactiae (n = 1; 19CS0081), St. gallolyticus (n = 1) and St. suis (n = 1)

Summary

Introduction

Mastitis is an infection or inflammation of the mammary gland. It is the most common bacterial disease on dairy farms and leads to a reduction in milk production, with high economic losses due to high costs of treatment and the need of disposing of potentially contaminated milk. Microorganisms like Escherichia (E.) coli, different Staphylococcus (S.) and Streptococcus (St.) species are transmitted through colostrum to young calves and can cause gastrointestinal and pulmonary diseases. In some cases, this leads to the death of calves [2].

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