Phenotypic Variants of Bacterial Colonies in Microbiological Diagnostics: How Often Are They Indicative of Differing Antimicrobial Susceptibility Patterns?

Phenotypic variants of bacteria are frequent in routine diagnostics and can display differing antimicrobial susceptibility patterns. We found that the likelihood of different antimicrobial susceptibility is low among PV. To save laboratory resources, only one isolate per PV could be tested to guide the antimicrobial treatment of patients.

The assessment of microbiological diagnostics’ credibility in Poland on the basis of the POLMICRO 2019 Program results

Introduction: This article describes the course and results of the 26th edition of the Polish National External Quality Assessment Scheme in Microbiology (POLMICRO). Aim: The aim is to assess the credibility of diagnostics conducted by microbiological laboratories in Poland, as well as the results and organization of the POLMICRO/ MIKOLOGIA (MYCOLOGY) and POLMICRO/SSE programs. Material and methods: The POLMICRO 2019 edition, according to the schedule, consisted of six rounds: five practical rounds and one theoretical round of an educational nature. The number of POLMICRO 2019 participants varied, depending on the round, from 430 to 438. In total, 443 laboratories took part in the program. The most (n = 438) laboratories took part in round I, and the least (n = 430) in round VI. Results: The shape and color of all test objects in the round devoted to microscopic preparations (4th round of POLMICRO 2019) were correctly assessed by 97.0% of laboratories (n = 419). Gram-negative rod strains belonging to the species Escherichia coli (PM-366, PM-367) and Klebsiella pneumoniae (PM-368, PM-369), from infection of the blood bed without a palpable site of infection, which were the subjects of the second round of POLMICRO 2019 studies, all participants correctly identified (100%; n = 433). While in the case of the MBL (metallo-β-lactamase) mechanism all participants (n = 439) correctly interpreted the presented picture, in the case of ESBL (β-lactamase with an extended substrate spectrum), seven laboratories (1.6%) misinterpreted the attached photos of phenotypic tests. Conclusions: In 2019, the Central Center for Quality Research in Microbiological Diagnostics, as previously planned, expanded its activity in the field of POLMICRO external laboratory control to include programs for mycological diagnostics (POLMICRO/ MIKOLOGIA) and diagnostics of etiological factors of gastrointestinal infections (POLMICRO/ SSE). Both the plan and the educational goals of the program have been achieved.

Microbiological diagnosis of tuberculosis in Russia in 2020:achievements and challenges

SummaryMonitoring the status of microbiological diagnostics of tuberculosis is of major national and international importance for achieving tuberculosis control objectives. Objective. To study and characterize the current state, major trends and current trends in the development of microbiological diagnostics of TB in progress. Materials and methods. The study covered health care organiza-tions of the executive authorities in the field of health services of the subjects of the Russian Federation. The data of industrial and single time statistical observation, as well as answers to special enquiries were studied. Results and discussion. Detection of TB patients by means of sputum microscopy is insufficient, amount-ing to 14.9% in new cases and 10.8% in recurrent ones. The increase in the share of pulmonary TB patients with a positive sputum microscopy up to 35.1% can be as-sociated with a worsening of active detection due to a new coronavirus infection. The share of newly-detected pulmonary TB patients with a positive culture for Myco-bacterium tuberculosis has also increased to 52.8%, but this is below the target (54.0%) and will not reach the target by 2024 (60.0%). The decrease is seen at both preanalytical and analytical phases, mainly in selected regions. The coverage by rapid methods was 87.4%, including WHO-recommended was 58.0%, which is be-low the target (90%). The coverage by drug sensitivity testing (DST) was 97.1% (target 100%). The coverage by DST of patients with resistance to rifampicin and fluoro-quinolones was 93.5%, the coverage by DST of patients with resistance to linezolid was 35.0%, to bedaquiline — 8.5%, to two drugs — 6.6%. Conclusion. It is advisable to intensify the targeted supervision by specialists in microbiological diagnostics of TB with low target values, paying attention to participation in quality assessment programmes, ensuring the possibility of DST to bedaqui-line and linezolid.

Features of the microbial landscape of patients' wounds at different periods of existence

Aim: to analyze the results of a microbiological diagnostics of wound swabs in patients with wounds of different duration. Material and methods. The results of bacteriological swabs of 405 wound samples from acute wounds (AW, up to 3 weeks, n=176) and chronic wounds (CW, more than 3 weeks, n=229) were analyzed. Results. Differences were found between the groups in the frequency of obtaining negative swabs (in AW – 24.7% [18.6; 30.9] cases), detection of monocultures (in AW – 50.9% [45.3; 56.5] cases) and microbial associations (in CW – 42.0% [35.4; 48.6]). Gram(+) bacteria – 73.1% and 62.1% (Staphylococcus spp., E. faecalis, Streptococcus gr. viridans) were dominant in wounds; Gram(-) bacteria (23.8% in AW and 33.6% in CW), represented by Enterobacterales, Pseudomonas and Acinetobacter, in CW were characterized by a wider species diversity. Only Gram(+) bacteria were found in AW up to 1 day of the existence; a change in the qualitative composition of microflora was manifested starting from the 10th day of the existence of wounds in the form of the appearance of Enterobacterales, Pseudomonas and Acinetobacter. The prevalence of methicillin-resistant S. aureus and coagulase-negative staphylococci strains was 52% and 54% for AW, 42% and 72% for CW, respectively. E. faecalis showed a high level of resistance to aminoglycosides and fluoroquinolones in all the wounds (>50% of isolates). Gram(+) bacteria were completely susceptible to vancomycin, teicoplanin, linezolid, and tigecycline. The sensitivity of A. baumannii and P. aeruginosa to carbapenems in all cases was high – 69% and 74%, to colistin – 100%. The sensitivity to aminoglycosides – amikacin, tobramycin in P. aeruginosa was 76% and 78%, in A. baumannii – 48% and 59%, respectively. K. pneumoniae showed complete sensitivity to carbapenems. Other Enterobacteriaceae were less resistant than K. pneumoniae. Conclusion. The results of a microbiological diagnostics of wound swabs made it possible to determine the qualitative structure of microflora and its differences depending on the duration of wound existence. The data obtained are the basis for further research, allowing to establish priority pathogens that disrupt the process of wound healing and are the cause of the formation of chronic wounds.