Critical points and potential pitfalls of outbreak of IMP-1-producing carbapenem-resistant Pseudomonas aeruginosa among kidney transplant recipients: a case-control study

Background Carbapenem-resistant Pseudomonas aeruginosa (CRPA) infection after kidney transplantation (KT) is associated with high mortality. Methods We analysed an outbreak of infection/colonization with IMP-1-producing CRPA on a KT ward, conducting a case-control study. Cases were identified through routine surveillance culture and real-time polymerase chain reaction (PCR) for carbapenemase performed directly from rectal swab samples. Controls were randomly selected from patients hospitalized on the same ward during the same period, at a ratio of 3:1. Strain clonality was analysed through pulsed-field gel electrophoresis (PFGE), and whole-genome sequencing was performed for additional strain characterization. Results CRPA was identified in 37 patients, in 51.4% through surveillance cultures and in 49.6% through clinical cultures. The median persistence of culture positivity was 42.5 days. Thirteen patients (35.1%) presented a total of 15 infections, of which 7 (46.7%) were in the urinary tract, among those, 30-day mortality rate was 46.2%. PFGE analysis showed that all of the strains shared the same pulsotype. Multilocus sequence typing analysis identified the sequence type as ST446. Risk factors for CRPA acquisition were hospital stay > 10 days, re-transplantation, urological surgical re-intervention after KT, use of carbapenem or ciprofloxacin in the last three months and low median lymphocyte count in the last three months. Conclusions KT recipients remain colonised by CRPA for long periods and could be a source of nosocomial outbreaks. In addition, a high proportion of such patients develop infection. During an outbreak, urine culture should be added to the screening protocol for KT recipients.

Comparaçäo entre diagnósticos clínicos e histológicos no pós-transplante renal / Comparison between clinical and histological diagnosis in kidney post-transplantation period

Objetivo. Para determinar o acerto obtido pelos diagnósticos efetuados em uma unidade de transplante renal, foram analisados 40 episódios de disfunçao renal aguda que ocorreram no período pós-transplante. Métodos. Os pacientes foram submetidos a biópsia renal por ocasiao do episódio de insuficiência renal ao mesmo tempo em que o diagnóstico clínico era realizado pelos membros da equipe. Resultados. Foram realizados 19 diagnósticos de necrose tubular aguda (NTA), 18 de rejeiçao celular aguda (RCA), dois de rejeiçao humoral (RH) e um de defrotoxicidade (NTX) pela ciclosporina A (CyA). O diagnóstico de NTA foi confirmado pela histologia em 84,21 por cento, o de RCA, em 83,33 por cento, o de RH em 100 por cento e o único diagnóstico de NTX realizado se apresentou como NTA à biópsia. No total, a clínica foi concordante com a histologia em 82,5 por cento das vezes. Conclusao. Os autores concluíram que esxiste uma boa acurácia nos diagnósticos clínicos de RCA, NTA e RH realizados em um centro experiente em transplante renal.