Carriage of antibiotic-resistant bacteria and etiology of postoperative infectious complications in infants with congenital heart defects

Objective. To determine resistant microorganisms carriage, the frequency and etiology of postoperative infectious complications in high-risk infants with congenital heart defects (CHD). Materials and Methods. The retrospective analysis included 489 patients admitted for surgical treatment for CHD. The median age was 0.23 (0–12) months. Swabs were taken from the oropharynx and rectum for microbiological examination no later than 72 hours after admission (a total of 978 samples). The growth of resistant microorganisms (ESBL and/or carbapenemase-producing Enterobacterales, resistant non-fermentative Gram-negative bacteria, MRSA and VRE) was recorded. Results. Of 489 patients, 128 (26.2%) were colonized with resistant bacteria. The majority of patients were carriers of ESBL-producers (81.3%), in some cases (24%) with concomitant production of several carbapenemases. The rate of VRE carriage was 21.1%, in 8 cases – in combination with other resistant microorganisms. MRSA was detected in 1.6% of carriers, other multidrug-resistant microorganisms – in 3.9% of carriers. In early postoperative period, 145⁄489 (29.7%) patients developed infectious complications. The ventilator-associated respiratory tract infections were the most common. In most cases (73.8%) infectious complications were caused by ESBL producers, in 43.9% of cases those microorganisms also produced carbapenemases. Resistant non-fermentative Gram-negative bacteria caused postoperative infections in 4.8% of cases. The rates of MRSA and VRE in infants with infectious complications were 3.4% and 1.4%, respectively. There were no differences in the incidence of infectious complications in colonized and non-colonized patients – 42⁄128 (32.8%) versus 103⁄361 (28.5%), respectively (p = 0.6). Postoperative infectious complications were caused by resistant microorganisms in colonized patients significantly more often than in non-colonized patients – 41⁄42 (97.6%) and 82⁄103 (79.6%) cases, respectively (p = 0.008). Conclusions. It is confirmed the active process of the introduction of resistant microorganisms into the hospital with the possible development of complications of the corresponding etiology. Gram-negative bacteria with different mechanisms of antibiotic resistance present the greatest problem. In order to manage this process, it is advisable to screen hospitalizing patients with the implementation of the infection control measures.