Biofilm-forming and antimicrobial resistance traits of staphylococci isolated from goat dairy plants.
BACKGROUND
Biofilm-associated antimicrobial resistance is of increasing importance to the maintenance and spread of foodborne pathogens in the food industry. This study aimed to investigate the ability to form biofilm and the antimicrobial resistance of staphylococci contaminating small-scale goat milk dairy plants.


METHODS
Sixty isolates were tested for antimicrobial resistance against 20 drugs by the microdilution method. Biofilm-forming traits were assessed by the microtiter plate method (MtP), Congo red agar method (CRA), and icaD gene detection by polymerase chain reaction (PCR).


RESULTS
High antimicrobial resistance to ampicillin (60/60; 100%), penicillin G (21/60; 35%), and erythromycin (15/60; 25%) was observed, but all isolates were susceptible to amoxicillin/K-clavulanate, ceftriaxone, ciprofloxacin, gentamicin, levofloxacin, linezolid, and moxifloxacin. No resistance to oxacillin or vancomycin was seen among Staphylococcus aureus. Twenty-seven isolates (27/60; 45%) were considered to form biofilm according to MtP, and similar biofilm-producing frequencies were observed in coagulase-negative staphylococci (CoNS) (20/44; 45.4%) and S. aureus (7/16; 43.7%). The icaD gene was observed only in S. aureus isolates. There was no association between biofilm production and antimicrobial resistance. A higher frequency of biofilm-producing staphylococci was found in isolates from bulk tank milk and hand swabs. On the other hand, isolates from pasteurized milk showed lower frequency of biofilm formation.


CONCLUSIONS
Staphylococci contaminating goat dairy plants are potential biofilm producers. The results suggest no association between the ability to form biofilm and antimicrobial resistance.
Center for Health Sciences, Federal University of Paraíba, João Pessoa, Brazil. myrellacariry@hotmail.com.
Myrella Cariry
MC
Lira
Paricia Emília Naves
PE
Givisiez
Francisca Geovânia Canafístula
FG
De Sousa
Marciane
M
Magnani
Evandro Leite
EL
De Souza
Denis Augusto
DA
Spricigo
Wondwossen Abebe
WA
Gebreyes
Celso José Bruno
CJ
De Oliveira
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001431:Bacteriological Techniques; D018441:Biofilms / Q000254:growth & development*; D003612:Dairying; D024881:Drug Resistance, Bacterial; D004783:Environmental Microbiology; D006041:Goats; D006225:Hand / Q000382:microbiology*; D006801:Humans; D008892:Milk / Q000382:microbiology*; D016133:Polymerase Chain Reaction; D013210:Staphylococcus / Q000187:drug effects / Q000302:isolation & purification* / Q000502:physiology*
D000900:Anti-Bacterial Agents