Incidence, antibiotic resistance and clonal relations of MRSA strains isolated from a Romanian university hospital

Antimicrobial Resistance of Staphylococcus aureus Isolated between 2017 and 2022 from Infections at a Tertiary Care Hospital in Romania

This study aimed to evaluate the frequency of isolation of Staphylococcus aureus from different pathological samples processed in the Microbiology Laboratory of the National Institute of Infectious Diseases "Prof. Dr. Matei Balș", Romania, between 1 January 2017 and 31 December 2022, aiming to establish the ratio of methicillin-resistant to methicillin-susceptible Staphylococcus aureus strains and the antibiotic resistance pattern of isolated microorganisms. The data of isolates originating from routine diagnostic tasks were analyzed retrospectively using laboratory data from the microbiology department. Up to 39.11% of Staphylococcus aureus strains were resistant to oxacillin (MRSA), with 49.97% resistance to erythromycin and 36.06% inducible resistance to clindamycin. Resistance rates to ciprofloxacin, rifampicin, gentamicin, and trimethoprim-sulfamethoxazole were 9.98%, 5.38%, 5.95%, and 0.96%, respectively. There was no resistance to vancomycin. Between 2017 and 2022, the percentage of MRSA strains decreased from 41.71% to 33.63%, sharply increasing to 42.42% in 2021 (the year of the COVID-19 pandemic, when the percentage of strains isolated from lower respiratory tract infections was higher than that of strains isolated from wounds or blood, as in previous years). This study showed a high percentage of MRSA strains (39.11% overall) with a higher proportion of these strains isolated from the blood (42.49%) compared to other clinical specimens.

Screening of mecI Gene in Staphylococcus Strains Isolated in Transylvania Region of Romania

In the last few decades, methicillin-resistant Staphylococcus aureus (MRSA) strains have become a serious health care problem. However, in the European Union/European Economic Area countries the prevalence of the invasive MRSA isolates has decreased in recent years; in Romania, the considerably high prevalence of these strains is still unchanged. In this study, 396 staphylococcal strains were screened using molecular biology techniques for the presence of the nucA, mecA, and mecI genes and for the detection of the possible mutations accumulated in the mecI gene. More than half of the collected Staphylococcus strains (59.34%) were determined as S. aureus, and 63 strains were considered as MRSA. Small number of MRSA strains (n = 6; 54.54% of invasive S. aureus) originated from hemoculture. The mecI gene was present in 22 MRSA strains and in 4 methicillin-resistant coagulase-negative staphylococci strains. The majority of the mecI-positive MRSA strains contained the C to T substitution at position 202; furthermore, one previously undescribed mutation (C to G transversion at nucleotide position 285) was detected in one MRSA strain.

Expanding PVL positive MRSA healthcare-associated infections outbreak in a newborns unit, caused by hospital hygiene shortcomings

A prolonged outbreak of Healthcare-Associated Infections (HCAIs) evolved since December 2013, in a Newborns Unit from Hospital A, sited in the North-Eastern development region, Romania. A first cluster consisted of 19 cases, of which 18 infections in newborns and 1 labour infectious complication in a mother. Except for five cases declared and treated in the Neonatology Unit as hospital-acquired infections, the other cases were discharged and further required rehospitalisation and treatment.

Eight of these innitialy discharged cases were readmitted to the Pediatric Surgery Unit and two others to the Pediatrics Unit of Hospital B, while three others were readmitted to three hospitals: one to the Pediatrics Unit of Hospital C, and other two to Hospital A and Hospital D, respectively. The mother with the labour infectious complication was readmitted to the Gynecology Unit of the Hospital A.

A number of fifteen Staphylococcus aureus (S. aureus) strains isolated from the HCAI first episode and 8 strains from 7 HCWs were received by „Cantacuzino” Institute, Nosocomial Infections and Antibiotic Resistance Laboratory from the County Public Health Directorate, for confirmation and molecular typing.

After a first round of interventions for infection control, a second episode bursted in Hospital A and our laboratory received six other S. aureus isolates from newborns, hospital environment, and HCWs.

Public Health interventions based on epidemiologic data and molecular microbiology results were finally successful. The evolution of all cases was favorable.

An important factor favoring the outbreak was the moving of the Birth Unit of Hospital A to an innapropriate location for an 18-month interval, more than innitially estimated, in relation to rehabilitation of the ward.

We considered to report this episode taking into account the unusual evolution, the risk of multiresistant bacterial strains spreading, and multiple unwanted consequences caused by shortcomings in providing appropriate hygiene conditions.

Molecular typing of MRSA and of clinical Staphylococcus aureus isolates from Iaşi, Romania

Romania is one of the countries with the highest prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the world. To obtain data on affiliation of MRSA to strains and clonal complexes and on the population of methicillin susceptible S. aureus (MSSA), clinical isolates from bloodstream infections, skin and soft tissue infections as well as from screening swabs were collected at hospitals in Ia?i, a city in the North-Eastern part of Romania. Isolates were characterised by microarray hybridisation. Nearly half of all isolates (47%), and about one third (34%) of bloodstream isolates were MRSA. The prevalence of the Panton-Valentine leukocidin (PVL) was also high (31% among MRSA, 14% among MSSA). The most common MRSA strain was a PVL-negative CC1-MRSA-IV that might have emerged locally, as a related MSSA was also common. PVL-positive CC8-MRSA-IV (“USA300”) and PVL-negative ST239-like MRSA-III were also frequently found while other MRSA strains were only sporadically detected. Among MSSA, PVL-positive CC121 as well as PVL-negative CC1, CC22 and CC45 predominated. Although this study provides only a snapshot of S. aureus/MRSA epidemiology in Romania, it confirms the high burden of MRSA and PVL on Romanian healthcare settings.

Molecular characterization and antibiotic susceptibility of Staphylococcus aureus from a multidisciplinary hospital in Romania

From 2004 to 2005, 60%-72% of invasive Staphylococcus aureus isolates from Romanian hospitals were resistant to methicillin (methicillin-resistant S. aureus [MRSA]), the highest frequency for any European nation. Few reports, however, have addressed the molecular characteristics of S. aureus in Romania. In this study, we utilized spa typing, multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec) typing, dru typing, pulsed-field gel electrophoresis, and detection of virulence factors to characterize 146 S. aureus strains isolated from 2004 to 2005 at the Clinic County Hospital in Braşov. Antibiotic susceptibility patterns for all MRSA isolates and patient demographic data were also obtained. Fifty-six strains (38.4%) were determined to be MRSA by susceptibility testing and SCCmec typing. All MRSA strains were resistant to beta-lactams and tetracycline, but susceptible to nitrofurans, vancomycin, and clindamycin, with inducible clindamycin resistance in 23/28 clindamycin-sensitive/erythromycin-resistant isolates. Molecular typing identified 15 clonal backgrounds (CC 1, 5, 8, 8/239, 9, 15, 20, 22, 25, 30, 45, 80, 97, 101, and 121), only 4 of which were associated with MRSA (CC 1, 8/239, 30, and 80). Spa types 35 (t127, CC 1) and 351 (t030, CC 8/239) accounted for 27.4% and 21.9% of all S. aureus strains, respectively, and 19.6% and 57.1% of all MRSA strains. Both hospital-associated (SCCmec type III) and community-associated (SCCmec type IV) elements were identified within MRSA strains, whereas Panton-Valentine leukocidin was detected in 10 MRSA and 12 methicillin-sensitive S. aureus strains. These results demonstrate the presence of various endemic S. aureus clones within the Clinic County Hospital in Braşov, suggestive of ongoing nosocomial and community transmission.

Quantitative differences in antibiotic resistance between methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains isolated in Hungary, Austria and Macedonia

The aim of this study was to compare the quantitative susceptibility of methicillin-resistant and -susceptible Staphylococcus aureus (MRSA and MSSA) strains from three European countries to nine antistaphylococcal agents. The antibiotic susceptibility of 274 MRSA and 284 MSSA strains from Hungary, Austria and macedonia was tested by the broth microdilution method. The clonal relationship of strains was determined by pulsed-field gel electrophoresis. Intermediate susceptibility to vancomycin appeared in Macedonian MRSA strains. Macedonian MRSA strains had high-level amikacin and gentamicin resistance. MSSA strains generally were susceptible to all drugs at minimum inhibitory concentrations (MIC(50)) except for gentamicin resistance in Macedonian strains. In Hungary and Austria a common antibiotic resistance phenotype of MRSA predominated, while in macedonia three other phenotypes were also prevalent. Geographical differences in the resistance of S. aureus are still high. Since resistance levels of MRSA and MSSA strains differ extensively, they should be considered separately for antibiotic resistance analysis.