Growing consumption of antibiotics and epidemiology of Clostridioides difficile infections in Poland: A need to develop new solutions.

Clostridioides (formerly Clostridium) difficile infections (CDIs) are becoming more common and more serious. C. difficile is the etiologic agent of antibiotic-associated diarrhea, pseudomembranous enterocolitis, and toxic megacolon while CDIs recur in 7.9% of patients. About 42.9 CDI cases/10,000 patient-days are diagnosed each day in Europe, whereas in Poland 5.6 CDI cases/10,000 patient-days are reported; however, the median for European countries is 2.9 CDI cases/10,000 patient-days. Epidemiology of CDIs has changed in recent years and risk of developing the disease has doubled in the past decade that is largely determined by use of antibiotics. Studies show that rate of antibiotic consumption in the non-hospital sector in Poland is much higher than the European average (27 vs. 21.8 DDD/1,000 patient-days), and this value has increased in recent years. Antibiotic consumption has also increased in the hospital sector, especially in the intensive care units - 1,520 DDD/1,000 patient-days (ranging from 620 to 3,960 DDD/1,000 patient-days) - and was significantly higher than in Germany 1,305 (ranging from 463 to 2,216 DDD/1,000 patient-days) or in Sweden 1,147 (ranging from 605 to 2,134 DDD/1,000 patient-days). The recent rise in CDI incidence has prompted a search for alternative treatments. Great hope is placed in probiotics, bacteriocins, monoclonal antibodies, bacteriophages, and developing new vaccines.

[Molecular characterization of Staphylococcus aureus strains isolated from surgical site infections of patients in southern Poland].

INTRODUCTION: The aim of the study was a molecular characterization of Staphylococcus aureus strains isolated from surgical site infections (SSIs) from patients in southern Poland, undergoing different surgical procedures, together with evaluation of the prevalence of antimicrobial resistance and the presence of virulence factors. MATERIALS AND METHODS: In this laboratory-based, multicenter study, non-repetitive 162 samples from SSI were collected from hospitalized patients (12 hospitals, n=139) or outpatients (n=23) in southern Poland between January 1 and December 31, 2013. In all S. aureus isolates, we investigated antimicrobial susceptibility, the presence of selected virulence genes (lukE, pvl, tsst-l and eta), and also conducted spa typing. RESULTS: Patients with SSI had a median age of 61 years; 54.9% were male. Prevalence of MRSA (29 strains, 17.9%) SSI per surgery type was 8.7% in orthopaedic, 17.7% in general and 42.9% in vascular surgery. Over 20% of strains were resistant for erythromycin (27.2%), clindamycin (23.5%). No resistance was found for linezolid, glycopeptides or tigecycline. Gene of Leukocidin (lukE) was the most frequently found gene. Spa typing identified 10 spa types; the two dominant types were t003 (41.4%) and t138(17.2%). CONCLUSIONS: The results show that after vascular surgery, there was an unexpectedly high prevalence of MRSA in SSIs in southern Poland. Conversely, the prevalence of MRSA was unexpectedly low following orthopaedics procedures. The surprisingly observation was the low virulence of the S. aureus strains among older patients.

Epidemiology, antibiotic consumption and molecular characterisation of Staphylococcus aureus infections--data from the Polish Neonatology Surveillance Network, 2009-2012.

BACKGROUND: Our aim was to determine and characterize S. aureus (SA) isolated from infections in newborns for antibiotic resistance, virulence factors, genotypes, epidemiology and antibiotic consumption. METHODS: Prospective surveillance of infections was conducted. Data about antibiotic treatment were analyzed. Antimicrobial susceptibility was assessed. PCR amplification was used to detect resistance and virulence genes. Typing methods such as PFGE, spa-typing and SCCmec were used. RESULTS: SA was found to be associated with 6.5% of infections. Methicillin-Resistant Staphylococcus aureus accounted for 32.8% of SA-infections. An incidence of MRSA-infections was 1.1/1000 newborns. MRSA-infections were diagnosed significantly earlier than MSSA-infections in these newborns (14th day vs. 23rd day (p=0.0194)). MRSA-infections increased the risk of newborn's death. Antibiotic consumption in both group was similar, but a high level of glycopeptides-usage for MSSA infections was observed. In the MRSA group, more strains were resistant to erythromycin, clindamycin, gentamicin and amikacin than in the MSSA group. Hla gene was present in 93.9% of strains, and seg and sei in 65.3% of strains, respectively. One dominant clone was found among the 14 MRSA isolates. Fifteen strains belonging to SCCmec type IV were spa-t015 and one strain belonging to SCCmec type V was spa-t011. CONCLUSIONS: Results obtained in the study point at specific epidemiological situation in Polish NICU (more detailed studies are recommended). High usage of glycopeptides in the MSSA infections treatment indicates the necessity of antimicrobial stewardship improvement and introducing molecular screening for early identification of infections.

Bloodstream Infections due to Enterobacteriaceae Among Neonates in Poland--Molecular Analysis of the Isolates.

Bloodstream infections (BSIs) are associated with a significantly increased risk of fatality. No report has been found about the molecular epidemiology of Enterobacteriaceae causing BSI in neonates in Poland. The aim of this work was to determine the antibiotic resistance profiles, virulence gene prevalence, the epidemiological and genetic relationships among the isolates from Enterobacteriaceae causing BSI in neonates with birth weight < 1501 g. Antimicrobial susceptibility testing was performed. PCR was performed to identify the presence of common beta-lactamase genes, virulence genes. PFGE and MLST were performed. The surveillance group contained 1,695 newborns. The incidence rate for BSIs was 5.9%, the fatality rate 15%. The most common species were Escherichia coli (n = 24) and Klebsiella pneumoniae (n = 16). CTX-M-15 was found in 6 E. coli, 8 K. pneumoniae, 1 Enterobacter cloacae strains. Among E. coli fimH (83.3%), ibeA (37.5%), neuC (20.8%) were the most frequent. PFGE demonstrated unique pulsotypes among E. coli. E. coli ST131 clone was found in 7 E. coli strains. PFGE of 16 K. pneumoniae strains showed 8 pulsotypes. Five isolates from one NICU belonged to one clone. MLST typing revealed 7 different ST with ST336 as the most prevalent. This study provides information about resistance, virulence and typing of Enterobacteriaceae strains causing BSI among neonates. E. coli and Klebsiella spp. isolated in this study have completely different epidemiology from each other.

The general status of patients and limited physical activity as risk factors of Methicillin-resistant Staphylococcus aureus occurrence in long-term care facilities residents in Krakow, Poland.

BACKGROUND: The aim of this study was to investigate the epidemiology and resistance of methicillin-resistant Staphylococcus aureus (MRSA) isolates from long-term care facilities (LTCF) residents and to analyze the potential risk factors for MRSA occurrence, defined as MRSA colonization and/or infection. METHODS: Point prevalence (PPS) and prospective incidence continuous study (CS) was carried out on a group of 193 residents in 2009-2010. RESULTS: Overall MRSA occurred (with or without infection) among 17.6% of residents. There was 16 cases of infections with SA aetiology, of which 10 (58.8%) were caused by MRSA. The MRSA prevalence in PPS was 12.9%, in CS infection incidence rate was 5.2%. Factors associated with MRSA occurrence were: general status of patients, limited physical activity, wound infections (odds ratio, OR 4.6), ulcers in PPS (OR 2.1), diabetes (OR 1.6), urinary catheterization (OR 1.6) and stool incontinence (OR 1.2). CONCLUSIONS: Our data indicate a need for screening of MRSA before hospitalization or transfer to rehabilitation centres, especially in a group of residents with limitations in physical activity - i.e. with the highest risk of MRSA. Results also suggest the need for contact precautions in patients with high risk of MRSA occurrence, only. Focus on the high-risk population might be a solution for the cost-effective surveillance.

Virulence and Antibiotic Resistance of Pseudomonas aeruginosa Isolated from Patients with Urinary Tract Infections in Southern Poland.

BACKGROUND: The aim of this study was to analyze the resistance and virulence of Pseudomonas aeruginosa strains causing urinary tract infections in in- and outpatients in Southern Poland. METHODS: The study included 83 inpatients and 66 outpatients; 36.9% were female. RESULTS: Monomicrobial infections accounted for 74.5%; polymicrobial infections occurred more frequently among inpatients (odds ratio, OR = 4.32, p = 0.0008). exoS and lasB were detected in 90 and 74% of isolates, respectively. aprA was present in 66%, pilB in 5% and pilA in 23% of isolates. Isolates from adults were more frequently resistant to fluoroquinolones (OR = 0.37, p = 0.029). Twenty-nine isolates were classified as multidrug resistant and 12 as extremely drug resistant, which occurred less frequently in patients <17 years (OR = 0.18, p = 0.024). Nine metallo-ß-lactamase-positive isolates were identified. blaSHV was present in 10, blaTEM in 6, blaOXA-10 in 3 and blaVIM-2 in 3 isolates. CONCLUSION: Antibiotic selection should be based on the knowledge of local antimicrobial susceptibilities to maximize the benefit for patients and minimize the risk of drug resistance.

Mode of delivery and other risk factors for Escherichia coli infections in very low birth weight infants.

BACKGROUND: Infections in newborns remain one of the most significant problems in modern medicine. Escherichia coli is an important cause of neonatal bloodstream and respiratory tract infections and is associated with high mortality. The aim of our study was to investigate the epidemiology of E. coli infection in Polish neonatal intensive care units (NICUs) and resistance to antibiotics, with particular reference to the safety of very low birth weight infants. METHODS: Continuous prospective infection surveillance was conducted in 2009-2012 in five NICUs, including 1,768 newborns whose birth weight was <1.5 kg. Escherichia coli isolates from different diagnostic specimens including blood, tracheal/bronchial secretions and others were collected. All isolates were tested using disk diffusion antimicrobial susceptibility methods. Pulsed-field gel electrophoresis was used to determine the possible horizontal transfer of E. coli among patients. RESULTS: The incidence of E. coli infections was 5.4% and 2.0/1,000 patient-days. The occurrence of E. coli infections depended significantly on the NICU and varied between 3.9% and 17.9%. Multivariate analysis that took into account the combined effect of demographic data (gender, gestational age and birth weight) and place of birth showed that only the place of hospitalisation had a significant effect on the E. coli infection risk. The highest levels of resistance among all E. coli isolates were observed against ampicillin (88.8%) and amoxicillin/clavulanic acid (62.2%). Among E. coli isolates, 17.7% were classified as multidrug resistant. Escherichia coli isolates showed different pulsotypes and dominant epidemic clones were not detected. CONCLUSIONS: Our data indicate that antibiotic prophylaxis in the presence of symptoms such as chorioamnionitis and premature rupture of membranes did not help reduce the risk of E. coli infection. Multivariate analysis demonstrated only one significant risk factor for E. coli infection among infants with a birth weight <1.5 kg, that is, the impact of the NICU, it means that both neonatal care and care during pregnancy and labour were found to be significant.

Molecular characterization and drug resistance of Escherichia coli strains isolated from urine from long-term care facility residents in Cracow, Poland.

BACKGROUND: The aim of this study was to assess the prevalence of multidrug-resistant Escherichia coli and extended-spectrum â-lactamases (ESBL) pathogens isolated from asymptomatic bacteriuria and urinary tract infections (UTIs), and the relationship between the phylogeny, antimicrobial resistance, and virulence among isolates in residents of 3 long-term care facilities (LTCF) in Krakow, Poland. MATERIAL AND METHODS: This was point prevalence study and prospective infection control in a group of 217 people. Urine samples were examined with standard microbiological methods and screened for the presence of blaCTX-M, blaSHV, and blaTEM. E. coli isolates were screened for 6 common virulence factors (VFs) and classified according to the rapid phylogenetic grouping technique. RESULTS: Among all the strains tested, 14 isolates (13.9%) expressed ESBL activity. A significant proportion of isolates were resistant to ciprofloxacin (32.7%, n=33). Resistance to trimethoprim/sulfamethoxazole was identified among 45 isolates (44.5%). Independent risk factors for the presence of an ESBL-producing strain were: UTI, urinary and/or fecal incontinence, bedridden, and low values of the Barthel and Katz Indexes. Gene sequencing identified 8 blaCTX-M-15, 1 blaCTX-M-3, 9 blaTEM-1, and 1 blaSHV-12. Among E. coli, no relationship between number of VF genes and phylogeny was found. The most prevalent virulence factor was fimH (82.1%). CONCLUSIONS: The findings of this study emphasize the need for further research on the epidemiology of multi-drug resistant organisms (MDRO) and ESBL in LTCF, including transmission patterns, rates of infection, and factors associated with infections. It may be necessary to extend the requirements and precautions to MDRO and ESBL-producers.

Typing of Staphylococcus aureus in order to determine the spread of drug resistant strains inside and outside hospital environment.

Staphylococcus aureus is one of the most important etiological factors of both nosocomial and community-acquired infections. Multidrug-resistant S. aureus is frequently isolated nowadays. Antibiotics used on the hospital ward exert a selective pressure on the strains and favor resistant strains. Multidrug-resistant and highly virulent strains can spread not only within the hospital but also between hospitals. Numerous studies show a predominance of one clone on a specific territory. The spread of such dangerous clones to neighboring countries and the entire continent is possible. Typing methods are very useful in infection control and prevention. Modern methods which are based on sequencing are necessary in rationalizing of infection control programs. Typing of Staphylococcus aureus includes methods that allow to determine the spread of drug-resistant pathogens. 'Gold standard' is pulsed-field gel electrophoresis (PFGE), which relies on separating the DNA fragments after restriction cutting. MLST (Multi Locus Sequence Typing) is based on a comparison of"housekeeping" gene sequences controlling the basic cell functions. With the MLST method, it is possible to demonstrate a broad, international spread of the specific clones. However, for epidemiological investigations, MLST seems to be too time-consuming and expensive to be used as a basic typing tool. The complementary method is spa typing, based on the sequencing of short repetitive sequences of the polymorphic X region from the gene encoding protein A. This method can be used for studying molecular evolution of S. aureus, as well as for testing for hospital outbreaks. It is faster and cheaper than MLST. It is also necessary to subtype the elements responsible for methycillin resistance (SCCmec), which allows to distinguish MRSA (Methicillin-resistant Staphylococcus aureus) clones with a common ancestor, but different epidemiological origin. All of those methods have their specific advantages and disadvantages and there is no single method efficient and suitable in any case.

Consumption of Antibiotics and Epidemiology of Clostridioides difficile in the European Union in 2016-Opportunity for Practical Application of Aggregate ECDC Data.

BACKGROUND: The most important pathomechanism of Clostridioides difficile infections (CDI) is post-antibiotic intestinal dysbiosis. CDI affects both ambulatory and hospital patients. AIM: The objective of the study was to analyze the possibility of utilizing databases from the European Centre for Disease Prevention and Control subject to surveillance for the purpose of identifying areas that require intervention with respect to public health. METHODS: The analysis encompassed data concerning CDI incidence and antibiotic consumption expressed as defined daily doses (DDD) and quality indicators for antimicrobial-consumption involving both ambulatory and hospital patients in 2016. RESULTS: In 2016, in the European Union countries, total antibiotic consumption in hospital and outpatient treatment amounted to 20.4 DDD (SD 7.89, range 11.04-39.69); in ambulatory treatment using average of ten times more antibiotics than hospitals. In total, 44.9% of antibiotics used in outpatient procedures were broad-spectrum antibiotics. We have found a significant relationship between the quality of antibiotics and their consumption: The more broad-spectrum antibiotics prescribed, the higher the sales of antibiotics both in the community sector and in total. CDI incidence did not statistically significantly correlate with the remaining factors analyzed on a country-wide level. CONCLUSION: Antibiotic consumption and the CDI incidence may depend on many national variables associated with local systems of healthcare organization and financing. Their interpretation in international comparisons does not give clear-cut answers and requires caution.

Long-Term Antibiotic Prophylaxis in Urology and High Incidence of Clostridioides difficile Infections in Surgical Adult Patients.

Clostridioides difficile infections are the main cause of antibiotic-related diarrhea. Most of them come in the form of healthcare-associated Clostridioides difficile infections (HA-CDI). The aim of the study was to analyze HA-CDI epidemiology and the relationship between antibiotic consumption and CDI epidemiology at St Luke's Provincial Hospital in Tarnow, Poland. In 2012-2018, surveillance of CDI was carried out in adult surgical wards at St Luke's Provincial Hospital. The data were collected in accordance with the methodology of the Healthcare-Associated Infections Surveillance Network (HAI-Net), European Centre for Disease Prevention and Control (ECDC), and the ATC/DDD system (Anatomical Therapeutic Chemical Classification System) of the World Health Organization. In total, in the study period, 51 cases of CDI involved CA-CDI (24.5%) and 147 were HA-CDIs (75.5%). The most CA-CDIs were found in the general surgery (32.6%) and urology (17.0%) wards. CA-CDI incidence was 0.7/1000 patients and for HA-CDI it was 2/1000 patients (4.4/10,000 patientdays (pds)). The highest HA-CDI incidence was in the neurosurgical departments (18/10,000 pds) and oncological surgery (8.4/10,000) pds. There was a significant positive correlation between CA-CDI and HA-CDI (correlation of 0.943, p < 0.001) and between the number of patients hospitalized and HA-CDI (correlation of 0.865, p = 0.012). The total antibiotic consumption amounted to 0.7 DDD/10,000 pds; it was the highest in the urology ward (0.84/10,000 pds) and 49.5% of the antibiotics were fluoroquinolones (0.41/10,000 pds). On the basis of regression coefficients, a positive correlation was demonstrated between the use of fluoroquinolones and the HA-CDI incidence rate. Both a high percentage of CDI cases and a high intake of antibiotics were recorded in the urology department. About half of all antibiotics were fluoroquinolones.

Exacerbations of Chronic Rhinosinusitis-Microbiology and Perspectives of Phage Therapy.

The chronically inflamed mucosa in patients with chronic rhinosinusitis (CRS) can additionally be infected by bacteria, which results in an acute exacerbation of the disease (AECRS). Currently, AECRS is universally treated with antibiotics following the guidelines for acute bacterial rhinosinusitis (ABRS), as our understanding of its microbiology is insufficient to establish specific treatment recommendations. Unfortunately, antibiotics frequently fail to control the symptoms of AECRS due to biofilm formation, disruption of the natural microbiota, and arising antibiotic resistance. These issues can potentially be addressed by phage therapy. In this study, the endoscopically-guided cultures were postoperatively obtained from 50 patients in order to explore the microbiology of AECRS, evaluate options for antibiotic treatment, and, most importantly, assess a possibility of efficient phage therapy. Staphylococcus aureus and coagulase-negative staphylococci were the most frequently isolated bacteria, followed by Haemophilus influenzae, Pseudomonas aeruginosa, and Enterobacteriaceae. Alarmingly, mechanisms of antibiotic resistance were detected in the isolates from 46% of the patients. Bacteria not sensitive to amoxicillin were carried by 28% of the patients. The lowest rates of resistance were noted for fluoroquinolones and aminoglycosides. Fortunately, 60% of the patients carried bacterial strains that were sensitive to bacteriophages from the Biophage Pharma collection and 81% of the antibiotic-resistant strains turned out to be sensitive to bacteriophages. The results showed that microbiology of AECRS is distinct from ABRS and amoxicillin should not be the antibiotic of first choice. Currently available bacteriophages could be used instead of antibiotics or as an adjunct to antibiotics in the majority of patients with AECRS.

Multi-locus sequence typing (MLST) of non-fermentative Gram-negative bacilli isolated from bloodstream infections in southern Poland.

Non-fermentative Gram-negative bacilli are now one of the most important causes of severe infections in Polish hospitals. Acinetobacter species are serious concern because of the high prevalence of multi-drug resistance among strains. Resistance profiles for 53 Gram-negative non-fermentative blood isolates were done. MLST was carried out using 44 strains representing the most commonly isolated species: A. baumannii, P. aeruginosa, and S. maltophilia. MLST revealed that all 22 A. baumannii belonged to sequence type (ST) 2. The P. aeruginosa isolates belonged to 10 different STs. Four S. maltophilia isolates matched STs present in the database (ST4, ST15, ST116, ST142), seven isolates showing novel sequence types. Among P. aeruginosa and S. maltophilia PFGE confirmed the genetical variety of strains.

Severe infections caused by multidrug-resistant non-fermentative bacilli in southern Poland.

BACKGROUND: The impact of multidrug-resistant organisms (MDROs), including non-fermentative bacilli (NFBs), is rising and underestimated, especially in intensive care units (ICUs). The growing prevalence of multidrug resistance (MDR) and extensive drug resistance (XDR) is challenging for clinicians, as the treatment options are limited. OBJECTIVES: The purpose of this study was to analyze the extent of the epidemiological problem of multidrugresistant, extensively drug-resistant and pandrug-resistant (PDR) non-fermentative bacilli isolated from pneumonia and bloodstream infections (BSIs) in patients hospitalized in southern Poland. MATERIAL AND METHODS: This study included 253 NFBs belonging to Acinetobacter sp. (ACI), Pseudomonas sp. (PAR), and Stenotrophomonas sp. (STM). The microorganisms were identified, and susceptibility testing was performed using a semi-automatic system. The different patterns of resistance were defined as MDR, XDR, or PDR strains. Epidemiological typing of A. baumannii from ICUs was performed by repetitive polymerase chain reaction (rep-PCR). RESULTS: More than half of the strains (57.7%) were isolated within ICUs. ACI-strains came significantly more often from ICU wards. The highest prevalence of ACI and PAR was found in pneumonia, whereas STM dominated in BSIs. ACIs were more frequently resistant than other pathogens to all studied antibiotics except colistin (n = 76; 58.9%), and they belonged to the XDR category. DiversiLab demonstrated the presence of 2 dominant clones in the ACI group, both classified as European Clone 2 (EUII). CONCLUSIONS: Our results indicate serious potential therapeutic problems related to high antibiotic resistance of ACI isolates. The stratification of drug resistance (MDR/XDR/PDR) may become an important tool for the assessment of public health epidemiology and microbiological hazards at the local, national, and international level. It allows clear presentation of the issues concerning the epidemiology of highly resistant bacilli, and the exchange of information between medical staff and local representatives of public health for the implementation of effective measures to reduce drug resistance.

Acinetobacter baumannii isolated from hospital-acquired infection: biofilm production and drug susceptibility.

Acinetobacter baumannii cause opportunistic nosocomial infections and is often multidrug resistant. It has ability to form biofilm. The possession of drug resistance mechanism and ability of biofilm formation seems to be the different way to enhancement of viability in stressful environment. In this study, we evaluate relation between these two factors. The biofilm formation was investigated in M63 medium with casein in microtiter plates, and the drug susceptibility was performed by disk diffusion methods. We found that 80-98% strains formed a biofilm. Strains showing sensitivity to amikacin and tobramycin from ICU produced more biofilm than strains showing resistance to these antibiotics. Ceftazidime-sensitive strains formed a smaller biofilm than resistant. The logistic regression shows association between drug resistance and strains originating from ICU. In case of ceftazidime, strong biofilm formation and descending from ICU reduced the likelihood of drug sensitivity. For other drugs such as aminoglycosides, fluoroquinolones, trimethoprim/sulfamethoxazole, and tetracycline, we found opposite relation (but it was not statistically significance). However, generally it seems that strong biofilm producers from ICUs are often more susceptible to antibiotics. This situation can be explained by the fact that bacteria protected in biofilm do not need mechanisms responsible for resistance of planktonic cells.

Virulence and antimicrobial resistance of Staphylococcus aureus isolated from bloodstream infections and pneumonia in Southern Poland.

OBJECTIVES: Staphylococcus aureus remains the most important cause of infections in hospitals and long-term care facilities. The aim of this study was to analyse the resistance, virulence, and epidemiological and genetic relationships of S. aureus from bloodstream infections (BSIs) and pneumonia from patients in Southern Poland. METHODS: All strains were tested for antimicrobial susceptibility using the disk diffusion method. Etest was also performed for vancomycin, teicoplanin, tigecycline, oxacillin, cefoxitin and penicillin. PCR amplification was used to detect selected virulence genes. The genetic similarity of methicillin-resistant S. aureus (MRSA) isolates was determined by spa typing and pulsed-field gel electrophoresis (PFGE). Using the BURP algorithm and the Ridom SpaServer database, spa types were clustered into different clonal complexes (spa-CCs). RESULTS AND CONCLUSIONS: MRSA strains were observed at a prevalence of 26.7%, but 88.6% of hospital-acquired infections were MRSA, with no difference between BSIs and pneumonia. The highest resistance was observed to erythromycin and tobramycin. None of the strains were resistant to linezolid, glycopeptides or tigecycline. The strains had no significant virulence factors and the number of virulence genes present did not correlate with the degree of drug resistance. PFGE typing showed relatively high diversity of strains. The majority of isolates belonged to spa type t003 (CC5).

Molecular Epidemiology and Drug Resistance of Acinetobacter baumannii Isolated from Hospitals in Southern Poland: ICU as a Risk Factor for XDR Strains.

The objectives of the present study were to investigate the carbapenemase and metallo-beta-lactamase genes of Acinetobacter baumannii clinical isolates by polymerase chain reaction (PCR) and real time PCR and to determine the molecular epidemiology of the strains using the DiversiLab tool. From these data, correlations between drug resistance, resistance genes, and epidemiological clones may be revealed. The study was conducted on 125 A. baumannii collected over the 2013 year. The majority of the isolates from both intensive care unit (ICU) and non-ICU cases originated from pneumonia infections (79.2%), isolates from blood infections accounted for 17.6% and 3.2% were from meningitis infections. In the ICU cases compared with the non-ICU cases, bloodstream infections were more frequently diagnosed (19.2% vs. 11.5%). Sixty percent of A. baumannii strains were resistant to all the antimicrobials tested with the exception of colistin. All strains were susceptible to colistin and polymyxin B. Extensively drug-resistant (XDR) strains accounted for 80.8% of the isolates tested and these XDR strains were more frequently isolated from ICU cases than from non-ICU cases (93.9% vs. 30.8%). Among the 101 isolates of A. baumannii exhibiting the XDR pattern of resistance, 80 possessed the blaOXA-24 gene and 29 had the blaOXA-23 gene. Only two isolates possessed the blaVIM gene. The presence of the ISAba1element was confirmed among 10 strains from patients hospitalized in the ICU. Using repetitive extragenic palindromic sequence PCR (DiversiLab typing), six clones and 12 unique strains were identified, of which two clones dominated. Most isolates belonging to clone 1 (66.7%) and clone 2 (85.5%) were susceptible only to colistin. In summary, it is clear from our findings and those of other studies that carbapenem resistance among A. baumannii strains presents a serious clinical problem worldwide. Furthermore, the presence of XDR international clone II in ICUs poses a potential risk for future outbreaks of A. baumannii infection and controlling A. baumannii infections in hospitals presents a serious challenge.

Virulence Potential of Staphylococcus aureus Strains Isolated from Diabetic Foot Ulcers Among Patients from Southern Poland.

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) was investigated among infected diabetic foot ulcers in hospitalized and nonhospitalized patients in southern Poland to assess the virulence patterns and antimicrobial resistance among these strains. MRSA was detected in 10.3% of all studied isolates, from the hospitalized patients only. The rest of the isolates was methicillin susceptible. The minimal inhibitory concentration that inhibits 50% of bacterial isolates (MIC50) for vancomycin was 1.0 mg/mL. The mupA gene was detected in six (8.8%) isolates, in one MRSA strain and five methicillin-sensitive S. aureus (MSSA) strains. Among the mupA-positive strains, two were resistant to mupirocin (1 MRSA and 1 MSSA). Such results raise serious concern about the usage of mupirocin in MRSA decolonization. The pvl gene was not detected among the study isolates. The majority of isolates (70.6%) possessed the lukE gene, with no significant difference in prevalence between MRSA and MSSA isolates. An interesting finding was the presence of enterotoxin genes among the study isolates. Diabetic foot may therefore be a reservoir of bacteria, containing genes localized on mobile genetic elements that could be easily transferred to other non-pathogenic strains. The prevalence of MRSA was alarmingly high (as also suggested by others), as evaluated by the presence of the mup gene among strains, highlighting the importance of appropriate clinical management of MRSA infections in patients with diabetic foot ulcers. In this group of patients, screening of ulcer samples before antimicrobial therapy would enable informed choices regarding the selection of antimicrobial agents (e.g. octenidine, authorized for the treatment of chronic wounds) maximizing the chances of positive therapy.

Molecular characterization of carbapenem-resistant Pseudomonas aeruginosa strains isolated from patients with urinary tract infections in Southern Poland.

Due to the clinical threat posed by multidrug-resistant (MDR) Pseudomonas aeruginosa and importance of virulence factors produced in infection, 21 carbapenem-resistant P. aeruginosa were analyzed. 42.8% metallo-beta-lactamases-positive strains were identified. 85.7% of strains were meropenem resistant. 14.2% of strains were MDR; 38%, extensively drug-resistant (XDR). ExoY was present in all strains; exoT, in 95.2%; exoS, in 90.5%; exoU, in 47.6%. Eight XDR strains were typed using multilocus sequence typing: 4 as ST235, 2 as ST260, 2 as ST654 and ST234. MDR P. aeruginosa were isolated from hospitalized patients and among those from the community. Our study demonstrates the serious clinical issues posed by MDR P. aeruginosa and underscores the need for new treatment.

The High Prevalence of Plasmid-Mediated Quinolone Resistance Among Very Low Birth-Weight Infants in Poland.

The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance (PMQR) determinants in Escherichia coli from neonatal intensive care units (NICUs) in Poland. The study was conducted on 80 E. coli isolates from different types of infections collected between 2009 and 2012. Six (5%) isolates were not susceptible to ciprofloxacin, 16% to ofloxacin, and 6.2% to levofloxacin. Among the 80 isolates, 27.5% carried at least one PMQR determinant (n = 22). qnrB was found in 8.8% of isolates (7/80), and qnrS was found in 2.5% (2/80). No isolates carrying qnrA, qnrD, qnrC, qepA, or oqxAB were found. The prevalence of aac(6')-Ib-cr was 27.5%, and 54.5% of the isolates contained aac(6')-Ib-cr and blaCTX-M. qnr-positive strains were more likely to produce extended-spectrum ß-lactamases (ESBLs) than qnr-negative strains, which may suggest an association between qnr and ESBLs (88.9% vs. 17%, p = 0.0003). PMQR-positive isolates had significantly higher ciprofloxacin MIC50 values (28.8-fold higher when comparing the MIC50 values) than the PMQR-negative strains (0.23 vs. 0.008 mg/L), regardless of the presence of quinolone resistance-determining region mutations. Five of the nine isolates, for which conjugation was performed successfully, harbored plasmids that contained CTX-M together with qnr and aac(6')-Ib-cr. Our data suggest that the number of qnr genes detected in E. coli from newborns may be related to the selection of qnr through antimicrobial exposure. Even if fluoroquinolones are not commonly used in the NICU, E. coli isolates may carry PMQR. The high prevalence of PMQR is of serious concern, as it may be horizontally transferred to other pathogenic bacteria.