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Synergistic antibacterial action of the iron complex and ampicillin against Staphylococcus aureus

Abstract

Resistance to antibiotics among bacteria of clinical importance, including Staphylococcus aureus, is a serious problem worldwide and the search for alternatives is needed. Some metal complexes have antibacterial properties and when combined with antibiotics, they may increase bacterial sensitivity to antimicrobials. In this study, we synthesized the iron complex and tested it in combination with ampicillin against S. aureus. An iron complex was synthesized and characterized using spectroscopy methods. Confirmation of the synergistic effect between the iron complex (Fe16) and ampicilin (AMP) was performed using zeta-potential, infrared spectra and FICI index calculated from the minimum inhibitory concentration (MIC) from the checkerboard assay. Cytotoxic properties of combination Fe16 + AMP was evaluated on eukaryotic cell line. Impact of combination Fe16 + AMP on chosen genes of S. aureus were performed by Quantitative Real-Time PCR. The MIC of Fe16 + AMP was significantly lower than that of AMP and Fe16 alone. Furthermore, the infrared spectroscopy revealed the change in the zeta-potential of Fe16 + AMP. We demonstrated the ability of Fe16 + AMP to disrupt the bacterial membrane of S. aureus and that likely allowed for better absorption of AMP. In addition, the change in gene expression of bacterial efflux pumps at the sub-inhibitory concentration of AMP suggests an insufficient import of iron into the bacterial cell. At the same time, Fe16 + AMP did not have any cytotoxic effects on keratinocytes. Combined Fe16 + AMP therapy demonstrated significant synergistic and antimicrobial effects against S. aureus. This study supports the potential of combination therapy and further research.

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Synergistic antibacterial action of the iron complex and ampicillin against Staphylococcus aureus

Author: Košarišťanová, Ludmila; Říháček, Martin; Suchá, Františka; Milosavljević, Vedran; Švec, Pavel; Matulová, Jana; Vojtová, Lucy; Antal, Peter; Kopel, Pavel; Patočka, Zdeněk; Adam, Vojtěch; Žůrek, Luděk; Doleželíková, Kristýna
Publisher: BMC
Year: 2023
DOI: 10.1186/s12866-023-03034-1
Source: https://dspace.vut.cz/bitstreams/b9d431e5-cb64-47c8-9a78-250b96e9b9c6/download
Kosa is ano ae al. BMC Mic obiology (2023) 23:288
h ps://doi.o g/10.1186/s12866-023-03034-1
RESEARCH Open Access
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BMC Mic obiology
Syne gis ic an ibac e ial ac ion o  hei on
complex andampicillin agains S aphylococcus
au eus
Ludmila Kosa is ano a1, Ma in Rihacek1, F an iska Sucha1, Ved an Milosa lje ic1, Pa el S ec1,
Jana Do azilo a2, Lucy Voj o a2, Pe e An al3, Pa el Kopel3, Zdenek Pa ocka4, Voj ech Adam1, Ludek Zu ek1 and
K is yna Dolezeliko a1*
Abs ac
Objec i es Resis ance o an ibio ics among bac e ia o clinical impo ance, including S aphylococcus au eus, is a se i-
ous p oblem wo ldwide and he sea ch o al e na i es is needed. Some me al complexes ha e an ibac e ial p ope -
ies and when combined wi h an ibio ics, hey may inc ease bac e ial sensi i i y o an imic obials. In his s udy, we
syn hesized he i on complex and es ed i in combina ion wi h ampicillin (Fe16 + AMP) agains S. au eus.
Me hods An i on complex (Fe16) was syn hesized and cha ac e ized using spec oscopy me hods. Con i ma ion
o he syne gis ic e ec be ween he i on complex (Fe16) and ampicillin (AMP) was pe o med using ζ–po en ial,
in a ed spec a and FICI index calcula ed om he minimum inhibi o y concen a ion (MIC) om he checke boa d
assay. Cy o oxic p ope ies o combina ion Fe16 + AMP was e alua ed on euka yo ic cell line. Impac o combina ion
Fe16 + AMP on chosen genes o S. au eus we e pe o med by Quan i a i e Real-Time PCR.
Resul s The MIC o Fe16 + AMP was signi ican ly lowe han ha o AMP and Fe16 alone. Fu he mo e, he in a ed
spec oscopy e ealed he change in he ζ–po en ial o Fe16 + AMP. We demons a ed he abili y o Fe16 + AMP o dis-
up he bac e ial memb ane o S. au eus and ha likely allowed o be e abso p ion o AMP. In addi ion, he change
in gene exp ession o bac e ial e lux pumps a he sub-inhibi o y concen a ion o AMP sugges s an insu icien
impo o i on in o he bac e ial cell. A he same ime, Fe16 + AMP did no ha e any cy o oxic e ec s on ke a inocy es.
Conclusions Combined Fe16 + AMP he apy demons a ed signi ican syne gis ic and an imic obial e ec s agains S.
au eus. This s udy suppo s he po en ial o combina ion he apy and u he esea ch.
Keywo ds S aphylococcus au eus, I on complex, Ampicillin, Syne gy, An imic obial ac i i y
*Co espondence:
K is yna Dolezeliko a
k [email p o ec ed]
Full lis o au ho in o ma ion is a ailable a he end o he a icle
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Kosa is ano ae al. BMC Mic obiology (2023) 23:288
In oduc ion
The eme gence o an imic obial esis ance is a p ob-
lem causing a global c isis and he a e o de elopmen
o new an imic obial agen s is no adequa e. Conse-
quen ly, in ec ions caused by mul id ug- esis an bac e ia
including S aphylococcus au eus a e o a g ea conce n
wo ldwide [1]. S aphylococcal in ec ions in humans and
animals a e commonly ea ed wi h β-lac am an ibio ics,
including ampicillin (AMP) [2]. A g ea selec i e p essu e
om he in ensi e and ex ensi e use o an ibio ics has
esul ed in β-lac am esis ance based on se e al mecha-
nisms such as e lux pumps, side opho es, and p oduc-
ion o β-lac amases [2–4]. Cu en ly, he majo i y o
clinical s ains o S. au eus a e β-lac amase posi i e [2],
use e lux pumps, and also p oduces side opho es [3, 4].
An imic obial p ope ies o me als ha e been known
o se e al decades [5] and hei combina ion wi h an i-
bio ics has been assessed in se e al s udies. Fo exam-
ple, i was shown ha β-lac ams oge he wi h sil e o
zinc oxide nanopa icles had g ea an imic obial ac i -
i y agains a ious mul id ug esis an bac e ia [6, 7].
I on has been also conside ed as a po en ial candida e
o combined ea men wi h an ibio ics [8]. I on is he
mos abundan ansi ion elemen in he human body
and a p omising an imic obial agen in he o m o a
me al complex. I on in he o m o a me al complex can
a ec bac e ial cells whe e hey cause oxida i e s ess,
inhibi espi a o y p ocesses and ATP p oduc ion,
inc ease cell hyd ophobici y, and acili a e hei pen-
e a ion ac oss he cell wall [7–9]. The e o e, combined
ea men s o e se e al ad an ages such as a lowe
po en ial o de eloping esis ance, addi i e o syne gis-
ic e ec s, inc easing he e ec i i y o an ibio ics, and
o e coming d ug esis ance [10]. Combina ion he apy
o an i on complex wi h β-lac ams has been es ed p e-
iously agains Esche ichia coli and i was mo e e ec i e
han an ibio ics alone [9].
The goal o his s udy was o syn hesize he i on
complex Fe16 and es i in combina ion wi h AMP
agains S. au eus. We also aimed o in es iga e he
mechanism o he syne gis ic ac ion o Fe16 + AMP
agains S. au eus and o e alua e whe he i has any
nega i e e ec s on euka yo ic cells ep esen ed by he
HaCaT cell line.
Resul s
Physico‑chemical cha ac e iza ion o Fe16 complex
andin e ac ion be weenFe16 andAMP
The in a ed spec um o Fe16 exhibi ed cha ac e is ic
bands o he Fe(II)- is(diimine) complexes. Also, he
elec onic spec a o Fe16 showed abso p ion bands
cha ac e is ic o Fe(II)- is(diimine) complexes (Fig.
S1Aa,b and Table S2). In e ac ions be ween Fe16 and
AMP we e con i med by he ζ–po en ial and ATR-
FTIR. The ζ–po en ial o Fe16 alone was + 55.8 mV
and AMP alone was -16.5 mV. The ζ–po en ial o
Fe16 + AMP was shi ed owa d sligh ly nega i e al-
ues -4.2mV (Fig. S2) indica ing he o ma ion o new
complexes. To u he s udy he in e ac ions be ween
Fe16 and AMP in he Fe16 + AMP complex, spec a o
Fe16, AMP, and Fe16 + AMP we e eco ded by ATR-
FTIR (Fig. S1C). No majo spec al al e a ions we e
obse ed compa ing he Fe16 spec um and he Fe16
sub ac ed spec a. Wi h he ocus on AMP and AMP
sub ac ed spec a, he wo signi ican band b oaden-
ings co esponding o alence ca boxyla e ib a ions
(COO−) a he wa e numbe alues o 1 590 and 1
370 cm−1 we e obse ed in spec um o Fe16 + A M P.
Theseca boxyla e g oups media e he in e ac ion in
Fe16 + AMP complex.
An an ibac e ial e icacy andsyne gis ic e ec o Fe16,
AMP, andFe16 + AMP onS. au eus by hechecke boa d
assay
The inhibi o y e ec om he checke boa d assay o
Fe16 + AMP agains S. au eus was signi ican ly g ea e
han ha o he indi idual compounds (Fig.1A). The
MIC alue o Fe16 31µg/ml and AMP 0.5µg/ml in com-
bina ion agains S. au eus was signi ican ly lowe han
ha o Fe16 and AMP alone wi h MIC alues o 125µg/
ml and 2µg/ml (Fig.1Ab). This inding also co ela ed
wi h he esul s o he FIC index. Isobolog am showed
he syne gis ic e ec be ween Fe16 (FICFe16 = 0.248)
and AMP (FICAMP = 0.250) (Fig.1Ac) based on he FIC
index calcula ion o he wo es ed componen s. The
an ibac e ial e ec o he Fe16 + AMP and i s syne gis-
ic e ec (≤ 0.5) agains S. au eus was con i med by he
FIC index 0.498.
Obse a ion o mo phological changes o S. au eus
a e Fe16, AMP andFe16 + AMP ea men
SEM mic oscopy o S. au eus ea ed wi h Fe16 + AMP
e ealed ha he in eg i y o he cell wall was comp o-
mised. In con as , un ea ed S. au eus cells e ained
hei coccus mo phology and he cell su ace was com-
pac (Fig. 1Ba). No mo phological change was also
obse ed in S. au eus cells ea ed wi h Fe16 (Fig.1Bb)
and AMP alone (Fig.1Bc). On he o he hand, sig-
ni ican mo phological changes we e obse ed a e
24h on S. au eus cells ea ed wi h Fe16 + AMP a he
sub-inhibi o y concen a ion (0.25 µg/ml) showing
damaged cells wi h dis up ed walls and memb anes
(Fig.1Bd).
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Kosa is ano ae al. BMC Mic obiology (2023) 23:288
Cy o oxici y p ope ies o Fe16, AMP andFe16 + AMP
The cy o oxic e ec o Fe16 on he HaCaT ke a inocy e cell
line was obse ed in he concen a ion ange o 8–125µg/
ml, whe eas o AMP no cy o oxici y was obse ed
(Fig.1C). A he concen a ion o 0.5µg/ml o Fe16 + AMP
he iabili y o ke a inocy es was 90.0% (Fig.1C).
Changes in he egula ion o selec ed genes o e lux
pumps, β‑lac amase andABC anspo e s a e  ea men
wi hFe16, AMP andFe16 + AMP
The exp ession o he e lux pump gene mepA signi i-
can ly inc eased a e all h ee ea men s ( old change in
he ange 3.43—9.33) al hough he e ec o AMP alone
Fig. 1 Aa Visualiza ion o he checke boa d o ma : G een boxes ep esen g ow h and whi e boxes inhibi ion. O ange box shows F ac ional
inhibi ion index, pink boxes demons a e posi ions o minimal inhibi o y concen a ions o Fe16 and AMP. Blue box is no- ea ed S. au eus
(Con ol). Ab image p esen s an ibac e ial and syne gy ac i i y wi h MIC and FIC esul s om checke boa d assay. The alues a e p esen ed
as he a e age om h ee independen expe imen s. Ac Isobolog am showing he syne gy e ec o Fe16 and AMP wi h FIC index ≤ 0.5 and able
demons a ing he he FIC index ca ego y scale. B Ex e nal mo phological changes o S. au eus a e exposu e o Fe16+AMP assessed by SEM.
Figu e Ba shows un ea ed S. au eus as a con ol, Bb demons a es S. au eus ea ed wi h Fe16 and Bc AMP alone a 0.125 ug/ml. Bd is S. au eus
ea ed wi h Fe16+AMP a 0.25 ug/ml. Red a ows indica e S. au eus mo phological changes. C Cy o oxic e ec s o Fe16, AMP and Fe16+AMP
a he di e en concen a ions on he HaCaT ke a inocy e cell line
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Kosa is ano ae al. BMC Mic obiology (2023) 23:288
was a signi icance le el p- alue < 0.01. The exp ession
o he no A gene also signi ican ly inc eased a e AMP
(2.8 old change) and Fe16 + AMP (3.1 old change) ea -
men s (Fig.2A). Gene exp ession o blaZ was down egu-
la ed, al hough no signi ican ly (p- alue > 0.2) (Fig. 2A).
The signi ican ly inc eased exp ession was de ec ed o
he anspo e genes pABC and huB a e exposu e
o Fe16 and Fe16 + AMP (p- alue < 0.05) (Fig.2B). Ampi-
cillin alone a ec ed he exp ession o pABC only. The
exp ession o he hi d ABC anspo e gene, h sA, was
down egula ed non-signi ican ly a e all ea men s
(Table S3).
Discussion
In ecen decades, many me al-based complexes ha e
been es ed o hei an imic obial p ope ies [1, 8]. I
has been shown ha i on exhibi s an imic obial e ec s
agains G am-posi i e and G am-nega i e bac e ia in he
o m o me al complex o nanopa icles [8, 11].
In he syn he ized complexes s uc u e [12], he di e -
ence in wa eleng hs obse ed o asymme ic and sym-
me ic ν(COO−) ib a ions indica es ha he compound
Fe16 adop ionic s uc u e and uma a e ions a e no
coo dina ed o he cen al a oms. The s ong bands can
be assigned o asymme ic ν(COO−) ib a ions bu su e
in e e ence wi h C = C and C = N s e ching ib a ions o
a oma ic ing [13]. Conside ing ha pKa alues o AMP
unc ional g oups (2.5/7.3) he ca boxylic acid became
anionic (COO¯), and amine g oup ca ionic (NH34+) [14].
Howe e , wi h inc ease he pH o e he AMP pKa alues
he a ge ed Fe16 complex a e in e ac ion wi h AMP
became dep o ona ed (anionic o m), which explains he
s ong dec ease o he Fe16 complex posi i e cha ge and
sligh inc ease o nega i e su ace cha ge o newly o med
complexes. Due o he shi o ca boxyla e asymme ic
alence ib a ions o highe wa enumbe s and symme -
ic alence ib a ion o lowe numbe s a e obse ed in
FTIR analysis. These spec al a ia ions a e connec ed
o he ca boxyla e g oup passing om he ee zwi e-
ionic COO− g oup o o ganome allic coo dina ion in
he Fe16 + AMP [15]. The band shi s in spec al egion
sugges in e ac ion o AMP phenyl wi h nphen in Fe16
ia π–π elec on dono –accep o complex sys em [16],
while he ib a ion posi ions ela ed o β-lac am ing in
AMP as well as NO2 unc ional g oup in Fe16 emains
unchanged. These da a indica e ha he key an ibac e ial
s uc u e in he complex emains una ec ed [17].
The an imic obial e ec o Fe16 + AMP on S. au eus
showed syne gis ic ac i i y a h e pheno ypic and an-
sc ip omic le el. P e iously, i was shown ha o he me -
als such as coppe , zinc, and i on in combina ion wi h
amoxicillin inc eased e ec i eness agains E. coli [9].
Al hough suscep ibili y o bac e ia o doped an ibio ics
wi h me al complexes has been shown be o e [18], in es-
iga ions on he i on complex a e a e [8]. Cell in eg i y
o S. au eus ea ed wi h Fe16 + AMP was comp omised
leading o cell dea h which co obo a es simila s udy
wi h sil e nanopa icles and an ibio ics [19]. Me al
Fig. 2 Gene exp ession a Log2 ( old change) o he ABC anspo e amily (A) and de ense sys em o S. au eus a e exposu e o AMP, Fe16
and Fe16 + AMP (B). Signi ican changes o Fe16, AMP and Fe16 + AMP in compa ison o ha o con ol a e ma ked wi h as e isks: *p- alue < 0.05,
**p- alue < 0.01, ***p- alue < 0.001
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Kosa is ano ae al. BMC Mic obiology (2023) 23:288
complexes inc ease he lipophilic cha ac e o he ansi-
ion me al ion and he e o e inc ease he hyd ophobici y
and acili a e hei pene a ion h ough he bac e ial cell
wall and memb ane [9]. In ou case, Fe16 + AMP appea s
o acili a e he pene a ion o AMP h ough he cell wall
o S. au eus. S udy o Panacek e al. (2016) showed ha
wi h AgNps sil e nanopa icles in combina ion wi h
an ibio ics including β-lac ams had also syne gis ic e ec
agains S. au eus [20].
I is impo an o no e ha no cy o oxic e ec s agains
he HaCaT cell line a e exposu e o Fe16 + AMP was
obse ed. In ecen yea s, many neu ological diso de s
ha e been a ibu ed o i on o e load; howe e , u he
s udies ha e op imized new complex me al compounds
in combina ion wi h a ious ma e ials o mode a e gen-
e al cy o oxici y [21, 22].
The combina ion o Fe16 + AMP a he sub-inhibi o y
concen a ion also likely led o dis up ion o he e lux
pumps and ha is consis en wi h he MICs esul s. The
s udy o he inhibi o y e ec o e lux pumps unde he
in luence o he i on complex alone and in combina ion
wi h an ibio ics has no been conduc ed p e iously.
Howe e , binding o i on oxide nanopa icles wi h
i ampicin o he ac i e si e o he e lux pump and con-
sequen blocking o i s unc ion has been demons a ed
[23]. Te mina ion o he p o on g adien , ollowed by
dis up ion o he memb ane po en ial and/o loss o
p o on mo i e o ce can lead o ailu e o he d i ing
o ce, which is essen ial o he unc ion o e lux pumps
[24, 25]. I is also assumed ha i on nanopa icles dis-
up he ac i i y o e lux pumps by gene a ing ROS
[25]. La ge me al oxides ha e he abili y o induce as e
elec on ans e kine ics o he ac i e si e o enzymes
[26]. Simila ly, up egula ion o mepA has been epo ed
using sil e nanopa icles and subsequen exposu e o
Ag+ ions [27]. Al hough he highes exp ession o mepA
and no A was eco ded a e he exposu e o he com-
bina ion o Fe16 + AMP, an inc eased exp ession o
hese wo genes was also de ec ed wi h Fe16 and AMP
sepa a ely. Fe16 alone could inc ease he exp ession o
mepA and no A due o he eac i e oxygen species ha
s ess he cells and dis up cellula componen s. Simila
o i ampicin ( unc ionalized i on nanopa icles wi h
an i- ube culosis d ugs), i causes damage o he p o-
ein subuni s and he ch omosome. This could lead o
he ailu e o he e lux pumps [28]. Ampicillin alone
also inc eased he exp ession o mepA and no A e lux
pumps, as shown o an ibio ics simila o β-lac ams
in o he s udies [29]. Howe e , he issue wi h di e en
classes o an ibio ics is he esidual ac i i y on bac e-
ial a ge s and he s eng hening o he selec ion o
esis ance mechanisms [30]. Mo eo e , he esul s o
he Fe16 and AMP componen s alone a e consis en
wi h he MIC esul s. As he down egula ion o blaZ
was demons a ed, he associa ion o an ibio ics wi h
me als supp esses β-lac amase hyd olase and he e-
o e an ibio ics can pass be e h ough he bac e ial
cell wall [31]. Ano he indica o o he ins abili y o he
de ense sys em o S. au eus was a change in he gene
exp ession o he ABC anspo e s. The o e exp es-
sion o he ABC anspo e s unde AMP ea men ,
in ou case he pABC gene, sugges s apid adap a ion
o he eac i e immune sys em and ele a ion o up ake
o i on in o he cell which is consis en wi h he MIC
esul s [32]. On he o he hand, he inc eased exp es-
sion o pABC and huB unde he in luence o Fe16
and Fe16 + AMP and he down egula ion o h sA in all
ea men s indica e insu icien up ake o i on by he
cell. Inac i a ion o in amemb ane p o eolysis o he
ABC anspo e was ound o inc ease he suscep ibil-
i y o S. au eus o se e al an imic obial agen s [33]. In
ano he s udy, he inhibi o y e ec o zinc on he me al
up ake by he ABC anspo e s a physiological con-
cen a ions was demons a ed [34]. Howe e , he num-
be o s udies ocused on his opic is low and u he
esea ch is needed. Based on ou esul s, we p opose
ha he applica ion o Fe16 + AMP causes s ess in S.
au eus, acili a es he pene a ion o AMP h ough he
cell wall, and dis up s he unc ion o e lux pumps and
ABC anspo e s (Fig.3). This oge he wi h insu i-
cien i on in ake leads o he bac e ial cell dea h.
In conclusion, Fe16 + AMP is a p omising new al e -
na i e o ea men o in ec ions caused by S. au eus
and po en ially o he pa hogenic bac e ia. Ou esul s
also demons a e ha his combina ion has no cy o-
oxic side e ec s on euka yo ic cells.
Me hods
Syn hesis o Fe16 = [Fe(nphen)3]( u)·7H2O andp epa a ion
o Fe16 + AMP combina ion
Fe ous uma a e, H2 u = uma ic acid and 5-ni o-
1,10-phenan h oline (nphen) (Sigma Ald ich, USA) we e
used o he syn hesis o he Fe16 = [Fe(nphen)3]( u)·7H2O
complex. The s uc u e o he Fe16 complex was syn he-
sized on he basis o he al eady known s uc u e o he
indi idual componen s men ioned abo e [35, 36]. I on
uma a e was mixed in 40.0ml o wa e wi h nphen dis-
pe sed in he same sol en and s i ed o 6.0h a 40.0°C.
Cha ac e iza ion o Fe16, AMP and Fe16 + AMP was con-
duc ed by spec oscopic me hods. The i on-an ibio ic
complex was p epa ed by mixing Fe16 wi h AMP in Mil-
liQ wa e a a concen a ion o 1.0mg/ml each and s i ed
a oom empe a u e o 24h a 45 pm.

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E alua ion o syne gis ic e ec s be weenFe16 andAMP
byζ – po en ial andin a ed spec a (FTIR)
Syne gism be ween Fe16 and AMP was e alua ed by
he ζ–po en ial and in a ed spec a (ATR-FTIR) [37,
38]. Samples we e subjec ed o analysis o DLS o ζ–
po en ial. The Fou ie ans o m in a ed spec ome e
equipped wi h a diamond c ys al was used o eco d
in a ed spec a o Fe16, AMP and Fe16 + AMP ia he
a enua ed o al e lec ance me hod (ATR-FTIR, Ve ex
70 , B uke , Bille ica, MA, USA). De ailed me hodology
is desc ibed in he Supplemen a y ile.
Cul i a ion o  es ed bac e ia
S aphylococcus au eus CCM 4223 (Czech Collec ion
o Mic oo ganisms, Masa yk Uni e si y, B no, Czech
Republic) was cul u ed on 5.0% Columbia blood aga
(LMS, Czech Republic) a 37.0°C o e nigh .
E alua ion o an imic obial ac i i y andan imic obial
syne gis ic e ec o Fe16, AMP andFe16 + AMP
bychecke boa d assay
An imic obial ac i i y and syne gis ic e ec o Fe16,
AMP and Fe16 + AMP was es ed by he checke boa d
assay [39]. B ie ly, Fe16 was placed in 96-well mic opla es
dilu ed wo old in Muelle Hin on b o h (Sigma Ald ich,
USA) along he e ical ows and AMP was c oss-dilu ed
ho izon ally by wo old se ial dilu ion. Bac e ial inocu-
lum o S. au eus was added in o each well o p oduce a
inal concen a ion o 1–2 × 106CFU/ml. The pla es we e
incuba ed a 37 ◦C o 24h. A e incuba ion, he bac-
e ial g ow h was assessed by obse ing he colo and
u bidi y o he solu ion. The es s we e ca ied ou in a
echnical iplica e. The in e ac ions be ween Fe16 and
AMP we e e alua ed by he ac ional inhibi o y con-
cen a ion index (FICI) calcula ed based on he o mula
(MIC o A in combina ion/MIC o A) + (MIC o B in
combina ion/MIC o B) [40].
Cy o oxic p ope ies o Fe16, AMP andFe16 + AMP
oneuka yo ic cell line
Cy o oxic p ope ies o Fe16, AMP, and Fe16 + AMP
we e e alua ed by he spon aneously ans o med ane-
uploidy immo al ke a inocy e cell line om he adul
human skin (HaCaT). Cell iabili y was quan i ied using
he MTT assay. De ailed me hodology is desc ibed in he
Supplemen a y ile.
Fig. 3 Mechanism o he an imic obial e ec o Fe16 + AMP causing s ess in S. au eus and dis up ion o unc ion o e lux pumps and ABC
anspo e s A. Impo o i on in o cells, needed by S. au eus o g ow h and me abolism, is dis up ed. B No A and MepA e lux pumps a e
no su icien o push Fe16 + AMP ou o cells
Page 7 o 8
Kosa is ano ae al. BMC Mic obiology (2023) 23:288
Cell mo phology o S. au eus a e Fe16, AMP
andFe16 + AMP ea men
Cell mo phology o S. au eus a e Fe16 + AMP ea -
men and Fe16 and AMP alone was obse ed by SEM.
S aphylococcus au eus was mixed wi h Fe16 + AMP in
concen a ion 0.25µg/ml (0.125µg/ml o each Fe16 and
AMP), wi h Fe16 (0.125µg/ml) and AMP (0.125µg/ml)
alone and cul u ed a 37.0°C o e nigh . A e incuba-
ion, samples we e ixed by glu a aldehyde (1.0%) and
incuba ed o 30 min a oom empe a u e. Samples
we e hen dehyd a ed using an ascending e hanol se ies
in ange 40—100% in se e al s eps. Cell mo phology was
examined by SEM on he Tescan MAIA 3 equipped wi h
a ield emission gun (Tescan L d., B no, Czech Republic).
Mo e de ailed me hods a e in he Supplemen a y ile.
RNA ex ac ion, pu i ica ion and e e se ansc ip ion
Fo RNA ex ac ion, S. au eus was cul u ed o e nigh
in Lu ia–Be ani (LB) b o h a 37.0°C and shaking a
120 pm wi h and wi hou sub-inhibi o y concen a-
ions o 0.25µg/ml o Fe16, AMP, and Fe16 + AMP. The
RNA ex ac ion was pe o med using TRIzol eagen ®
(TRIzol Reagen , In i ogen, Ca lsbad, CA) acco ding
o he manu ac u e ins uc ions. The isola ed RNA was
pu i ied by e hanol RNA/DNA p ecipi a ion and e e se
ansc ip ion was pe o med wi h he ansc ip o i s
s and cDNA syn hesis ki o RT-PCR (Roche, Man-
nheim, Ge many) based on he manu ac u e ins uc-
ions using 500.0ng RNA.
Quan i a i e eal‑ ime PCR
Quan i a i e eal- ime PCR analysis was pe o med using
he qTOWER3 sys em (Analy ik Jena, Jena, Ge many)
wi h poB as he housekeeping gene. Resul s we e isu-
alized as log2 old change (ΔΔC ) calcula ions. All p im-
e s we e designed using he IDT sys em. Mo e de ailed
me hods a e in he Supplemen a y ile.
S a is ical e alua ion
The unpai ed - es be ween un ea ed and ea ed sam-
ple om ΔC alues o biological iplica e was used o
de e mine he impac o ea men s on de ense sys em o
S. au eus. All s a is ical analysis and g aphical isualiza-
ions we e done using G aphPad P ism 8.0.1. (G aphPad
So wa e, CA, USA).
Abb e ia ions
AMP Ampicillin
ATR-FTIR A enua ed o al e lec ance-Fou ie - ans o m in a ed spec oscopy
DLS Dynamic ligh sca e ing
Fe16 I on complex
Fe16 + AMP Combina ion o i on complex wi h ampicillin
FIC F ac ional Inhibi o y Concen a ion
MIC Minimum inhibi o y concen a ion
RPM Re olu ions pe minu e
Supplemen a y In o ma ion
The online e sion con ains supplemen a y ma e ial a ailable a h ps:// doi.
o g/ 10. 1186/ s12866- 023- 03034-1.
Addi ional ile1: TableS1. P ime s used o Quan i a i e Real–Time PCR.
TableS2. Elec onic spec al da a o aqueous solu ions o Fe16. TableS3.
Exp ession o he all es ed genes o S. au eus shown as Fold change a e
exposu e en i onmen al s ess o AMP, Fe16 and Fe16+AMP ela i e o no
ea ed S. au eus wi h use o poB as housekeeping gene. Figu e S1. Phys-
ico-chemical cha ac e iza ion o he Fe16 complex. Figu e S2. ζ-po en ial
o Fe16, AMP and Fe16+AMP measu ed in MiliQ wa e a pH 8.2.
Acknowledgemen s
This wo k was suppo ed by he ERDF “Mul idisciplina y esea ch o inc ease
applica ion po en ial o nanoma e ials in ag icul u al p ac ice” (No. CZ.02.1.01/
0.0/0.0/16_025/0007314). CzechNanoLab p ojec LM2018110 unded by MEYS
CR is acknowledged o he inancial suppo o he measu emen s a CEITEC
Nano Resea ch In as uc u e.
Au ho s’ con ibu ions
PK and PA pe o med he syn hesis and cha ac e iza ion o he i on complex
and ga e commen s. LV, JD and VM did he expe imen s and e alua ion wi h
commen s o he syne gis ic e ec be ween he i on complex and ampicil-
lins. FS pe o med he cy o oxici y expe imen and PS SEM mic oscopy. MR
designed expe imen o Quan i a i e Real-Time PCR and e alua ion o esul s.
LK pe o med expe imen s, analyzed and commen ed mic obiological and
molecula pa s and comple ion and w i ing o he a icle. ZP designed s a-
is ical e alua ion. VA edi ed he manusc ip . KD and LZ designed he p ojec ,
supe ised he expe imen s and w o e he epo . All au ho s ha e ead and
app o ed he inal manusc ip .
Funding
ERDF “Mul idisciplina y esea ch o inc ease applica ion po en ial o nanoma-
e ials in ag icul u al p ac ice” CZ.02.1.02/0.0/0.0/16_025/0007314 and he
CzechNanoLab p ojec LM2018110 unded by MEYS CR.
A ailabili y o da a and ma e ials
Da a is a ailable on he depa men sha e d i e and can be uploaded when
eques ed. The i s au ho may be con ac ed i someone wan s o eques he
da a om his s udy.
Decla a ions
E hics app o al and consen o pa icipa e
No applicable.
Consen o publica ion
No applicable.
Compe ing in e es s
The au ho s decla e no compe ing in e es s.
Au ho de ails
1 Depa men o Chemis y and Biochemis y, Facul y o Ag iSciences,
Mendel Uni e si y in B no, B no, Czech Republic. 2 Cen al Eu opean Ins i u e
o Technology, Uni e si y o Technology, B no, Czech Republic. 3 Depa men
o Ino ganic Chemis y, Facul y o Science, Palacky Uni e si y, Olomouc, Czech
Republic. 4 Depa men o Fo es Managemen and Applied Geoin o ma ics,
Facul y o Fo es y and Wood Technology, Mendel Uni e si y in B no, B no,
Czech Republic.
Page 8 o 8
Kosa is ano ae al. BMC Mic obiology (2023) 23:288
Recei ed: 8 May 2023 Accep ed: 28 Sep embe 2023
Re e ences
1. Nasi i So a i S, Zobi F. Recen S udies on he an imic obial ac i i y o ansi-
ion me al complexes o g oups 6–12. Chemis y. 2020;2(2):418–52.
2. Tee haisong Y, Au a kool N, Si ichaiwe chakoon K, K ubphachaya P, Kupi -
ayanan S, Eumkeb G. Syne gis ic ac i i y and mechanism o ac ion o
S ephania sube osa Fo man ex ac and ampicillin combina ion agains
ampicillin- esis an S aphylococcus au eus. J Biomed Sci. 2014;21(1):90.
3. Iqbal G, Faisal S, Khan S, Shams DF, Nadhman A. Pho o-inac i a ion and
e lux pump inhibi ion o me hicillin esis an S aphylococcus au eus using
hiola ed cobal doped ZnO nanopa icles. J Pho ochem Pho obiol B Biol.
2019;192:141–6.
4. Saha R, Saha N, Dono io RS, Bes e el LL. Mic obial side opho es: a mini
e iew. J Basic Mic obiol. 2013;53(4):303–17.
5. Sa anya J, JoneKi uba a hy S, Chi a S, Za ouk A, Kalpana K, La anya K, e al.
Te aden a e schi base complexes o ansi ion me als o an imic obial
ac i i y. A ab J Sci Eng. 2020;45(6):4683–95.
6. Fayaz AM, Balaji K, Gi ilal M, Yada R, Kalaichel an PT, Venke esan R. Biogenic
syn hesis o sil e nanopa icles and hei syne gis ic e ec wi h an ibio ics:
a s udy agains g am-posi i e and g am-nega i e bac e ia. Nanomedicine.
2010;6(1):103–9.
7. Ye Q, Chen W, Huang H, Tang Y, Wang W, Meng F, e al. I on and zinc ions,
po en weapons agains mul id ug- esis an bac e ia. Appl Mic obiol
Bio echnol. 2020;104(12):5213–27.
8. Claudel M, Schwa e JV, F omm KM. New an imic obial s a egies based on
me al complexes. Chemis y. 2020;2(4):849–99.
9. H ioua A, Loudiki A, Fa ahi A, Lagh ib F, Bakasse M, Lah ich S, e al. Compl-
exa ion o amoxicillin by ansi ion me als: physico-chemical and an ibac e-
ial ac i i y e alua ion. Bioelec ochemis y. 2021;142:107936.
10. San os JVdO, Po o ALF, Ca alcan i IMF. Po en ial applica ion o combined
he apy wi h lec ins as a he apeu ic s a egy o he ea men o bac e ial
in ec ions. An ibio ics. 2021;10(5):520.
11. A ias LS, Pessan JP, Viei a APM, Lima TMTd, Delbem ACB, Mon ei o DR. I on
oxide nanopa icles o biomedical applica ions: a pe spec i e on syn hesis,
d ugs, an imic obial ac i i y, and oxici y. An ibio ics. 2018;7(2):46.
12. Kopel P, T a nicek Z, Zbo il R, Ma ek J. Syn hesis, X- ay and Mossbaue s udy
o i on(II) complexes wi h i hiocyanu ic acid ( cH(3)). The X- ay s uc-
u es o Fe(bpy)(3) ( cH) cen e do 2bpy cen e do 7H(2)O and Fe(phen)
(3) ( cH(2))(ClO4) cen e do 2CH(3)OH cen e do 2H(2)O. Polyhed on.
2004;23(14):2193–202.
13. Ludwig C, De idal J-L, Casey WH. The e ec o di e en unc ional g oups
on he ligand-p omo ed dissolu ion o NiO and o he oxide mine als.
Geochim Cosmochim Ac a. 1996;60(2):213–24.
14. Shi ani M, Akba i-Ade gani B, Rashidi Nodeh H, Shahabuddin S. Ul asonica-
ion- acili a ed syn hesis o unc ionalized g aphene oxide o ul asound-
assis ed magne ic dispe si e solid-phase ex ac ion o amoxicillin, ampicillin,
and penicillin G. Mic ochimica Ac a. 2020;187(11):634.
15. on Wi én N, Khod H, Hide RC. Hyd oxyla ed phy oside opho e species
possess an enhanced chela e s abili y and a ini y o I on(III)1. Plan Physiol.
2000;124(3):1149–58.
16. Na h H, Sha ma P, F on e a A, Ba celo-Oli e M, Ve ma AK, Das J, e al.
Phenan h oline-based Ni(II) coo dina ion compounds in ol ing uncon en-
ional disc e e uma a e-wa e -ni a e clus e s and ene ge ically signi ican
coope a i e e na y π-s acked assemblies: an ip oli e a i e e alua ion and
heo e ical s udies. J Mol S uc . 2022;1248:131424.
17. Tippe DJ, S ominge JL. Mechanism o ac ion o penicillins: a p oposal
based on hei s uc u al simila i y o acyl-D-alanyl-D-alanine. P oc Na l Acad
o Sci. 1965;54(4):1133–41.
18. El-Gamel NEA. Me al chela es o ampicillin e sus amoxicillin: syn hesis, s uc-
u al in es iga ion, and biological s udies. J Coo d Chem. 2010;63(3):534–43.
19. Vazquez-Muñoz R, Meza-Villezcas A, Fou nie PGJ, So ia-Cas o E, Jua ez-
Mo eno K, Gallego-He nández AL, e al. Enhancemen o an ibio ics
an imic obial ac i i y due o he sil e nanopa icles impac on he cell
memb ane. PLoS One. 2019;14(11):e0224904.
20. Panáček A, Smékalo á M, Kiliano á M, P ucek R, Bogdano á K, Večeřo á
R, e al. S ong and Nonspeci ic Syne gis ic An ibac e ial e iciency o
an ibio ics combined wi h sil e nanopa icles a e y low concen a ions
showing no cy o oxic e ec . Molecules. 2016;21(1):26.
21. Singh AV, Vyas V, Mon ani E, Ca elli D, Pa azzoli D, Oldani A, e al. In es iga-
ion o in i o cy o oxici y o he edox s a e o ionic i on in neu oblas oma
cells. J Neu osci Ru al P ac . 2012;3(3):301–10.
22. Richa dson DR, Lok HC. The ni ic oxide–i on in e play in mammalian cells:
anspo and s o age o dini osyl i on complexes. Biochim Biophys Ac a
Gen Subj. 2008;1780(4):638–51.
23. Padwal P, Bandyopadhyaya R, Meh a S. Polyac ylic acid-coa ed i on oxide
nanopa icles o a ge ing d ug esis ance in mycobac e ia. Langmui .
2014;30(50):15266–76.
24. Nalla hamby PD, Lee KJ, Desai T, Xu X-HN. S udy o he mul id ug memb ane
anspo e o single li ing Pseudomonas ae uginosa cells using size-dependen
plasmonic nanopa icle op ical p obes. Biochemis y. 2010;49(28):5942–53.
25. Hasani A, Madhi M, Gholizadeh P, ShahbaziMoja ad J, Ahanga zadehRezaee
M, Za ini G, e al. Me al nanopa icles and consequences on mul i-d ug
esis an bac e ia: e i ing hei ole. SN Appl Sci. 2019;1(4):360.
26. Banoee M, Sei S, Naza i ZE, Ja a i-Fesha aki P, Shah e di HR, Moballegh A,
e al. ZnO nanopa icles enhanced an ibac e ial ac i i y o cip o loxacin
agains S aphylococcus au eus and Esche ichia coli. J Biomed Ma e Res Pa
B: Appl Bioma e . 2010;93(2):557–61.
27. Singh N, Rajwade J, Paknika KM. T ansc ip ome analysis o sil e nanopa -
icles ea ed S aphylococcus au eus e eals po en ial a ge s o bio ilm
inhibi ion. Colloids Su B: Bioin e aces. 2019;175:487–97.
28. Dey N, Kama chi C, Vick am AS, Anba asu K, Thanigai el S, Palani elu J, e al.
Role o nanoma e ials in deac i a ing mul iple d ug esis ance e lux pumps
– a e iew. En i on Res. 2022;204:111968.
29. Wang Z, Zhang P, Ding X, Wang J, Sun Y, Yin C, e al. Co-deli e y o ampicillin
and β-lac amase inhibi o by selenium nanocomposi e o achie e syne gis-
ic an i-in ec i e e iciency h ough o e coming mul id ug esis ance. Chem
Eng J. 2021;414:128908.
30. Mahamoud A, Che alie J, Alibe -F anco S, Ke n WV, Pagès J-M. An ibio ic
e lux pumps in G am-nega i e bac e ia: he inhibi o esponse s a egy. J
An imic ob Chemo he . 2007;59(6):1223–9.
31. Wang R, Lai T-P, Gao P, Zhang H, Ho P-L, Woo PC-Y, e al. Bismu h an imi-
c obial d ugs se e as b oad-spec um me allo-β-lac amase inhibi o s. Na
Commun. 2018;9(1):439.
32. Loss G, Simões PM, Valou F, Co ês MF, Gonzaga L, Be go M, e al. S aphylo-
coccus au eus Small Colony Va ian s (SCVs): News om a ch onic p os he ic
join in ec ion. F on Cell In ec Mic obiol. 2019;9:363.
33. Jonsson I-M, Juu i JT, F ançois P, AlMajidi R, Pie iäinen M, Gi a d M, e al.
Inac i a ion o he Ecs ABC anspo e o S aphylococcus au eus a enua es
i ulence by al e ing composi ion and unc ion o bac e ial wall. PloS One.
2010;5(12):e14209.
34. Remy L, Ca iè e M, De é-Bobillo A, Ma ini C, Sanguine i M, Bo ezée-
Du an E. The S aphylococcus au eus Opp1 ABC anspo e impo s nickel
and cobal in zinc-deple ed condi ions and con ibu es o i ulence. Mol
Mic obiol. 2013;87(4):730–43.
35. Li Z-F, Zheng Y-Q. Syn hesis and c ys al s uc u e o [Fe(phen)3]L·2H2L·4H2O
(H2L = uma ic acid). J Coo d Chem. 2005;58(10):883–90.
36. Kopel P, T á níček Z, Zbořil R, Ma ek J. Syn hesis, X- ay and Mössbaue s udy
o i on(II) complexes wi h i hiocyanu ic acid ( cH3): he X- ay s uc u es
o [Fe(bpy)3]( cH)·2bpy·7H2O and [Fe(phen)3]( cH2)(ClO4)·2CH3OH·2H2O.
Polyhed on. 2004;23(14):2193–202.
37. Va ap asad K, López M, Núñez D, Jaya amudu T, Sadiku ER, Ka hikeyan C,
e al. An ibio ic coppe oxide-cu cumin nanoma e ials o an ibac e ial
applica ions. J Mol Liq. 2020;300:112353.
38. Saïed N, Aïde M. Ze a po en ial and u bidime y analyzes o he e alua-
ion o chi osan/phy ic acid complex o ma ion. J Food Res. 2014;3(2):71.
39. Khunbu s i D, Naimon N, Sa chasa apo n K, In hong N, Kaewmongkol S,
Su ja i S, e al. An ibac e ial ac i i y o solanum o um lea ex ac and i s
syne gis ic e ec wi h oxacillin agains me hicillin- esis an S aphyloccoci
isola ed om dogs. An ibio ics. 2022;11:302.
40. Mgbeahu uike EE, S ålnacke M, Vuo ela H, Holm Y. An imic obial and syne -
gis ic e ec s o comme cial pipe ine and pipe longumine in combina ion
wi h con en ional an imic obials. An ibio ics. 2019;8(2):55.
Publishe ’s No e
Sp inge Na u e emains neu al wi h ega d o ju isdic ional claims in pub-
lished maps and ins i u ional a ilia ions.