Antibiotic susceptibility among Staphylococcus epidermidis isolated from prosthetic joint infections, with focus on doxycycline

Abstract

In recent years, coagulase-negative staphylococci such as Staphylococcus epidermidis have gained importance as nosocomial pathogens, especially in immunocompromised patients and prosthetic joint infections (PJIs). These infections are often long lasting and difficult to treat due to the production of bacterial biofilm and the transformation of the bacteria into a stationary growth phase. Rifampicin is able to penetrate the biofilm, but to reduce the risk of development of rifampicin resistance it should be used in combination with an additional antibiotic. In this study we used Etest to investigate the antimicrobial susceptibility of 134 clinical isolates of S. epidermidis obtained from PJIs to six oral antibiotics: doxycycline, rifampicin, linezolid, fusidic acid, clindamycin, and ciprofloxacin. We also performed synergy testing on doxycycline in combination with each of the remaining antibiotics. Ninety-three (69%) of the 134 isolates were susceptible to doxycycline, 94/134 (70%) to rifampicin, 56/134 (42%) to clindamycin, 25/134 (19%) to ciprofloxacin, 81/134 (60%) to fusidic acid, and 100% to linezolid. Thirty-two (80%) of the 40 isolates not fully susceptible to rifampicin were susceptible to doxycycline. Doxycycline in combination with each of the other investigated antibiotics exerted an additive effect on nearly half of the isolates, with the exception of clindamycin, which displayed an even higher percentage of additive effect (69%). To conclude, as the majority of the S. epidermidis isolates were susceptible to doxycycline, this antimicrobial agent may provide a potential alternative for combination therapy together with rifampicin.

Species and antimicrobial susceptibility testing of coagulase-negative staphylococci in periprosthetic joint infections

“…We found 30.2% S. epidermidis strains resistant to rifampicin, which is comparable with results of previous studies [17], where strains showed between 30% and 39% resistance [20].…”

“…These discordant results could be explained by a large proportion of SE in previous studies on CNS PJIs. No CNS strain was resistant to linezolid or daptomycin, as described in previous studies [20]. Linezolid resistance was identified as the most frequent mechanism in CNS due to a mutation in 23S rDNA [21] in rare studies.…”

Doxycycline inhibits electric field-induced migration of non-small cell lung cancer (NSCLC) cells

“…Doxycycline is an antibiotic widely used to treat bacterial infections 21–23 . Numerous studies have reported that doxycycline exhibits anti-tumour and pro-apoptotic activity.…”

Monoclonal Antibodies Specific to the Extracellular Domain of Histidine Kinase YycG of Staphylococcus epidermidis Inhibit Biofilm Formation

“…Staphylococcus epidermidis has emerged as one of the most critical opportunistic pathogens of nosocomial infections in recent years because of the increase in frequency of invasive procedures ( Vuong et al, 2003 ; Chessa et al, 2015 ). The main pathogenicity associated with S. epidermidis involves the formation of biofilms on implanted medical devices ( Rupp, 2014 ; Hamad et al, 2015 ). The presence of the bacteria in biofilms drastically reduces the efficacy of conventional antibiotics and the host immune system, and this leads to persistent or recurrent infections ( Wolcott et al, 2010 ; Romling and Balsalobre, 2012 ).…”