SUSCEPTIBILITY PATTERNS AND CROSS-RESISTANCE OF: ANTIMICROBIAL PEPTIDES (DEFENSINS, BACTERIOCINS, IONOPHORES), AMINOGLYCOSIDES, MACROLIDES, PENICILLINS, CEPHALOSPORINS, AND CARBAPENEMS IN <i>Listeria</i> SPP.

SCHMALRECK A.F.¹, HOF H.², BECKER K.³, FEGELER W.⁴, CZAIKA V.^5
1MBS - Microbiology, 80086 Munich, Germany.
²Labor Limbach, 69126 Heidelberg, Germany.
³Institute of Medical Microbiology, University of Münster, 48149 Münster, Germany.
⁴Institute of Medical Microbiology, University of Münster, 48149 Münster, Germany.
⁵Universitätsmedizin Berlin, Klinik für Dermatologie, Venerologie und Allergologie, Charité Campus Benjamin Franklin,12203 Berlin, Germany.

Received : 08-04-2014     Accepted : 24-04-2014     Published : 05-08-2014
Volume : 3     Issue : 1       Pages : 39 - 61
World Res J Antimicrob Agents 3.1 (2014):39-61

Conflict of Interest : None declared

Tested with 38 antimicrobial agents (AMA), the overall susceptibility-rates (S) of the 24 Listeria species were 56%; for aminoglycosides 62%, ß-lactams 60%, cephalosporins 10%, carbapenems 100%, penicillins 98%, and macrolides 29%, and were similar to those reported in literature. The resistance rates of the antimicrobial peptides (pore-formers), which included the bacteriocin nisin with 17%, the antimicrobial peptides (defensins) alamethicin (100%) and magainin (13%), and the ionophores ionomycin (96%), and lonomycin (4%) were higher than reported in literature. Cross-resistance (CR) was observed in all 24 Listeria isolates with a number from 7 (18%) up to 25 (66%) of 38 AMA tested, exerting 6 “multiple antibiotic resistance indexing” (MAR) groups. The pore-former demonstrated CR, expressed in 5 different susceptibility patterns (SPs) in all 24 strains. Listeria populations with resistance to only one AMA (sPC) of the aminoglycoside group (AMG) was found in 15 SPs, and a 4 to 10 fold AMG-parallel-resistance (PR) in 19 cases. AMG-CR to nisin was found in 12 cases, to alamethicin in 15, to magainin in 3, to ionomycin in 14 and to lonomycin in one case. Cephalosporins revealed 6 SPs with two to seven-fold PR, and 11 with four to 11-fold CR with the pore-formers. Penicillins demonstrated only one SP with three-fold PR (MEZ-PIS-PIT), and showed no cross-resistance to the pore-formers. With macrolides, one population was resistant to only troleandomycin and two, with PR to oleandomycin and rosaramycin could be detected. Nine SPs with three- to sevenfold CR with pore formers were obtained. Carbapenems showed no PR, and no CR with the pore-formers. The time dependent evaluation of the Listeria minimum inhibitory concentrations (MICs) demonstrated no statistically significant increase in MICs from 1940 up to 1998. However, the number and characteristics of the susceptibility patterns demonstrated a slightly increase (6%) in cross-resistance, respectively changes of SP characteristics. The results indicate that resistance to the AMAs is not a new phenomenon but originates ahead of the modern antibiotic area. Susceptibility pattern analysis proofed to be a valuable tool in analysing and determining of parallel- and cross-resistance.