Poultry as a vector for emerging multidrug resistant Enterococcus spp.: First report of vancomycin (van) and the chloramphenicol-florfenicol (cat-fex-cfr) resistance genes from pigeon and duck faeces.

Although commonly regarded as human and animal intestinal tract commensals, Enterococcus spp. have emerged as important nosocomial pathogens due to their intrinsic or acquired resistance to a number of antibiotics. Poultry has been suggested to be a reservoir for antibiotic resistance that may aggravate the problem of transmission of enterococci infections. Between January and December 2016, 106 Enterococcus spp. were isolated from a total of three poultry species. The collection included isolates recovered from chickens (n = 30), ducks (n = 35) and pigeons (n = 41). All enterococci isolates were screened for their ability to form biofilm. The antibiotic susceptibility was determined against 13 antibiotics using the disc diffusion method. The presence of the eight resistance genes, vanA, vanB, vanC, catA, catB, fexA, fexB and cfr was determined by PCR. All 106 isolates were resistant to clindamycin, whereas majority of isolates (>90%) were resistant to erythromycin, oxytetracycline, doxycycline, gentamycin, ciprofloxacin, norfloxacin, and vancomycin. All isolates produced biofilms and were classified as extensive drug-resistant. MARindices for all isolates was determined to be > 0.8, indicating that they have been recovered from high risk contamination sources. The cfr resistance gene was not detected in any of the 106 enterococci isolates, whereas the chloramphenicol resistance genes catA and catB were found in 18.9% (20/106) of the isolates. Interestengly, fexA 11.9% (15/106), fexB 8.7% (11/106), vanA 18.9% (20/106), vanB 25.5% (27/106), and vanC 33% (35/106) genes were also determined in our study. The present study highlights the emergence of a linezolid sensitive-vancomycin resistant enterococci, which lacks the cfr gene reporting also for the first time the detection of van, fex and cat -genes in Enterococcus species recovered from chickens, ducks and pigeons in Egypt suggesting that poultry species could be potential vectors for transmission of multidrug resistant enterococci posing a public health risk.

Characterization and susceptibility of streptococci and enterococci isolated from Nile tilapia (Oreochromis niloticus) showing septicaemia in aquaculture and wild sites in Egypt.

BACKGROUND: The present investigation was an endeavor into the elucidation of the disease-causing pathogen of streptococcosis in Nile tilapia (Oreochromis niloticus) in Egypt affecting adult fish cultured and wild fish in the Nile river. Fish were obtained from commercial fishermen, collected as part of their routine fishing activities. The researchers observed the routine fishing process and selected fish for use in the study, at the point of purchase from the fisherman. RESULTS: Diseased fish showed exophthalmia with accumulation of purulent and haemorrhagic fluid around eyes, and ventral petechial haemorrhages. The Post mortem examination revealed, abdominal fat haemorrhage, pericarditis and enlargement of the liver, spleen and kidney. Gram-stained smears revealed the presence of Gram-positive cocci, ß-hemolytic, oxidase and catalase negative. Analysis of the 16S rRNA gene confirmed that the 17 tilapia isolates studied were 6/17 Enterococcus faecalis, 2/17 Enterococcus gallinarum, 3/17 Streptococcus pluranimalium, 2/17 Aerococcus viridans, 1/17 isolate of each Streptococcus dysgalactiae, Streptococcus anginosus, Lactococcus garvieae and Granulicetella elegans/Leuconostoc mesenteroides cremoris. It should be noted that there was no mixed infection. Multiple resistance was observed and the most frequent antibiotic combination was penicillin, ampicillin, vancomycin, chloramphenicol, rifampicin, ofloxacin, clindamycin, erythromycin and tetracycline representing eight classes. CONCLUSIONS: Consequently, we concluded that Streptococcus species are an emerging pathogen for Nile tilapia aquaculture in Egypt and to be considered as a new candidate in the warm water fish diseases in Egypt with special reference to L. garvieae, S. dysgalactiae in addition to L. mesenteroides cremoris which was not reported before from tilapia and taking into consideration their zoonotic implications for public health.