Multiple antibiotic resistance index, fitness and virulence potential in respiratory Pseudomonas aeruginosa from Jamaica

Abstract

Respiratory infections are common causes of morbidity and mortality worldwide. We sought to assess the multiple antibiotic resistance (MAR) index, fitness and virulence potential in Pseudomonas aeruginosa from patients with lower respiratory tract infections. Isolates were assessed for antimicrobial susceptibility, in vitro competitive fitness, and pigment, elastase and rhamnolipid production. Oxidative stress tolerance was determined on both planktonic and biofilm cells, and virulence potential was tested in a plant model. Mean MAR index for isolates was 0.34 (range 0.17-0.50). Whilst isolates exhibited good biofilm formation in the presence of ciprofloxacin, there was no significant difference in biofilm production over the concentration range assessed. Several drug-resistant strains were out-competed by a susceptible strain even in the presence of antibiotic. H 2 O 2 exerted a greater oxidative stress than tert-butylhydroperoxide and, as expected, biofilms were more resistant than planktonic cells. Whilst most (81 %) isolates were pigmented there was no significant difference between pigmented and non-pigmented isolates when elastolytic activity was compared (P.0.05). More than half of the isolates produced the quorum sensing mediator rhamnolipid and infection of the plant model by bacteria occurred whether elastase or rhamnolipid was present or absent. These data suggest that non-pigmented strains of P. aeruginosa might pose an equally significant microbiological threat as pigmented strains even though pigment production appeared to be strongly associated with elastase expression. Whilst dual expression of elastase and rhamnolipid by these bacteria would cause severe tissue damage (as seen in the plant model), non-production of either does not prevent bacteria from causing serious infection.

Campylobacteriosis Agents in Meat Carcasses Collected from Two District Municipalities in the Eastern Cape Province, South Africa

“…In Bolivia, Argentina, Chile, and Peru, many Campylobacter strains are resistant to quinolones (47-78%) as well as tetracycline (40.8-65.9% in Argentina and Bolivia), erythromycin (58.6% to 61.4% in Bolivia and Chile), and ampicillin (47.2% in Argentina) [89]. The value of the MAR index is 0.2, and the MAR index is a good risk assessment tool used to distinguish high-and low-risk areas where antibiotics are overused [90]. The MAR indices of the isolates were calculated, and 77.83% were found to have a MAR index greater than 0.2, while 17 isolates had MAR indices of 1.0 ( Table 5).…”

Qualitative Detection and Isolation of Bacteria from Surfaces of Canned Drinks Sold in Ugbor, Benin City

“…E. coli is widely or generally regarded as indicator of fecal contamination suggesting that the refrigerator internal surfaces are frequently contaminated by import of contaminated raw foods or by poor personal hygiene. The harmless or less virulent species or strains are definitely no threats to public health but if the MAR index is greater than 0.2 as stipulated by Krupernman (1983), Chitanand et al (2010) and Davis and Brown (2016) there is every reason to worry about the public health of the community. The MAR index according to Chitanand et al (2010) reflects the pathogen's importance as a public health threat and more so, its origin (whether or not antibiotics have been used).…”

“…The MAR index is a good tool for health risk assessment which identifies if the isolates are from a region of high or low antibiotic usage. A MAR index of 0.2 and above indicates a 'high-risk' source of contamination (Davis and Brown 2016). The multiple antibiotic resistance MAR index was determined for each isolate using the methods delineated by Chitanand et al (2010) by dividing the percentage of antibiotic resistance of the total percentage of antibiotics used in the study.…”

Pseudomonas aeruginosa as a Powerful Biofilm Producer and Positive Action of Amikacin Against Isolates From Chronic Wounds

“…Delay of wound healing is becoming one of the major problems imposing heavy burden on public health, and its common factor is the presence of bacterial flora on chronic wounds (2). Pseudomonas aeruginosa is the most common microorganism isolated from chronic wounds, often found as biofilm producer, that acts as a barrier in wound healing and shows resistance to antimicrobial therapy (2)(3)(4). Pseudomonas aeruginosa is a Gram-negative and rodshaped opportunistic pathogen that is a major causative microorganism in wound infections, delaying the wound healing process.…”