Post‐surgical wound infections involving Enterobacteriaceae with reduced susceptibility to β‐lactams in two Portuguese hospitals

Abstract

The post-surgical period is often critical for infection acquisition. The combination of patient injury and environmental exposure through breached skin add risk to pre-existing conditions such as drug or depressed immunity. Several factors such as the period of hospital staying after surgery, base disease, age, immune system condition, hygiene policies, careless prophylactic drug administration and physical conditions of the healthcare centre may contribute to the acquisition of a nosocomial infection. A purulent wound can become complicated whenever antimicrobial therapy becomes compromised. In this pilot study, we analysed Enterobacteriaceae strains, the most significant gram-negative rods that may occur in post-surgical skin and soft tissue infections (SSTI) presenting reduced β-lactam susceptibility and those presenting extended-spectrum β-lactamases (ESBL). There is little information in our country regarding the relationship between β-lactam susceptibility, ESBL and development of resistant strains of microorganisms in SSTI. Our main results indicate Escherichia coli and Klebsiella spp. are among the most frequent enterobacteria (46% and 30% respectively) with ESBL production in 72% of Enterobacteriaceae isolates from SSTI. Moreover, coinfection occurred extensively, mainly with Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (18% and 13%, respectively). These results suggest future research to explore if and how these associations are involved in the development of antibiotic resistance.

Molecular Characterization of ESBL-Producing Enterobacteriaceae in Northern Portugal

“…As reported in previous Portuguese [9–12, 14, 15, 17–19], Spanish [8, 20, 21], and other European [6] studies E. coli and K. pneumonia are the species where ESBL is the most frequently identified. In this study E. coli was the most frequent ( n = 131) organism expressing ESBL phenotypes, more than twofold of the K. pneumonia ( n = 59), the second most frequent.…”

“…Crude preparations of β -lactamases from clinical strains transconjugants were obtained by sonication in phosphate buffer, pH 7.0, as described previously [15]. Briefly crude extracts were concentrated and a nitrocefin solution was added.…”

“…Each tube was heated in a microwave oven at 600–700 W for 2 min to burst the cells and release their DNA. PCR was performed as described previously [15]. The recovered bands from agarose gels were cloned for further sequencing.…”

“…Other regions either from Portugal vs Spain are represented in different shades of green and gray or, respectively. Data was collected from the present study (yellow) and from several studies in these two countries [8–12, 14, 15, 17–26]. [ECO: Escherichia coli ; ENT: Enterobacter spp .…”

Two cases of monomicrobial intraabdominal abscesses due to KPC - 3 Klebsiella pneumoniaeST258 clone

“…Thus, intestinal colonization with MDR organisms, such as carbapenem resistant K. pneumoniae , may be a risk factor in critically ill surgical patients. Post-surgical wound infections involving these organisms have also been described [15]. …”