Wastewater Surveillance Detected Carbapenemase Enzymes in Clinically Relevant Gram-Negative Bacteria in Helsinki, Finland; 2011–2012

Antimicrobial resistance profiling of pathogens helps to identify the emergence of rare or new resistance threats and prioritize possible actions to be taken against them. The analysis of wastewater (WW) can reveal the circulation of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARG) among the catchment communities. Here, we analyzed WW influent samples to determine the prevalence of carbapenemase genes-carrying Gram-negative bacteria (Carba-GNB) in Helsinki, Finland. This study set important historical reference points from the very early stage of the carbapenemase era, during the period 2011–2012. A total of 405 bacterial isolates grown on CHROMagarKPC (n = 195) and CHROMagarESBL (n = 210) from WW influent samples were collected between October 2011 and August 2012 and were analyzed. The bacterial DNA from the isolates was extracted, and the prevalence of carbapenemases genes blaKPC, blaNDM, blaGES, blaOXA-48, blaIMP, blaIMI, and blaVIM were screened with multiplexed PCR. All carbapenemase-positive isolates were identified taxonomically to species or genus level with matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The nucleic acid extraction was successful for 399 isolates, of which 59 (14.8%) were found to carry carbapenemase genes. A total of 89.8% of the carbapenemase positive isolates (53 out of 59) were obtained from CHROMagarKPC plates and only 10.2% (six out of 59) were obtained from CHROMagar ESBL plates. Among the Carba-GNB isolates, 86.4% were blaGES (51 out of 59), 10.2% were blaKPC (six out of 59), and 3.4% were blaVIM (two out of 59). The most common carba-gene, blaGES, was carried by 10 different bacterial species, including Aeromonas spp., Enterobacter spp., and Kluyvera spp.; the blaKPC gene was carried by Escherichia coli, Klebsiella pneumoniae, and Kluyvera cryocescens; and the blaVIM gene was carried by Aeromonas hydrophila/caviae and Citrobacter amalonaticus. This study emphasizes that wastewater surveillance (WWS) can be an additional tool for monitoring antimicrobial resistance (AMR) at the population level.

Performance of the EUCAST disc diffusion method and two MIC methods in detection of Enterobacteriaceae with reduced susceptibility to meropenem: the NordicAST CPE study

Objectives

To examine performance of EUCAST disc diffusion and supplementary MIC methods for detection of Enterobacteriaceae with reduced susceptibility to meropenem using EUCAST screening recommendations.

Methods

Sixty-one Nordic laboratories delivered data on EUCAST disc diffusion (n = 61), semi-automated meropenem MIC (n = 23; VITEK2, n = 20 and Phoenix, n = 3) and gradient meropenem MIC (n = 58) methods. The strains (n = 27) included the major carbapenemase classes (A, n = 4; B, n = 9; D, n = 6) involved in the global spread of carbapenemase-producing Enterobacteriaceae (CPE) and non-CPE strains (n = 8) covering a range of broth microdilution (BMD) meropenem MICs.

Results

A triplicate Klebsiella variicola (meropenem MIC 0.5 mg/L) harbouring OXA-48 and Escherichia coli ATCC 25922 showed an overall good precision. Meropenem zone diameters below the EUCAST screening cut-off (<27 mm) were reported for strains with MIC ≥1 mg/L (n = 21), irrespective of resistance mechanism. For three strains (MIC = 0.5 mg/L) with OXA-48/-181, eight laboratories provided meropenem zone diameters above the screening cut-off. Very major errors (VMEs) were not observed. The overall distributions of major errors (MEs) and minor errors (mEs) were 9% and 36% (disc diffusion), 26% and 18% (VITEK2) and 7% and 20% (gradient MIC), respectively. Differences in ME and mE distributions between disc diffusion and MIC gradient tests compared with semi-automated methods were significant (P < 0.0001), using BMD MICs as a reference for categorization.

Conclusions

The EUCAST disc diffusion method is a robust method to screen for CPE but isolates with meropenem MICs <1 mg/L pose challenges. The high ME rate in semi-automated methods might deter appropriate use of carbapenems in CPE infections with limited therapeutic options.

Sharing more than friendship - transmission of NDM-5 ST167 and CTX-M-9 ST69 Escherichia coli between dogs and humans in a family, Finland, 2015

Carbapenemase-producing Enterobacteriaceae (CPE) have rarely been reported in dogs, and never in animals in Finland. However, in April 2015, two meropenem-resistant Escherichia coli were identified from two dogs in one family. Both dogs suffered from chronic otitis externa. Methods: Epidemiological and molecular investigations (pulsed-field gel electrophoresis (PFGE), multilocus sequence typing) were conducted to investigate the source of infection and transmission routes. Results: In both dogs and one family member New Delhi metallo-beta-lactamase (NDM-5)-producing multidrug-resistant ST167 E. coli was found. Whole genome sequencing confirmed that the isolates were identical or only had one or two allelic differences. Additionally, the dogs and humans of the family carried an identical extended-spectrum beta-lactamase (ESBL) CTX-M-group 9 E. coli ST69 strain, indicating interspecies transmission. While the original source remains unclear, human-to-canine transmission is possible. No carbapenems had been administered to the dogs, but exposure to numerous other antimicrobials likely sustained the bacteria and supported its propagation in the canine host. Conclusion: To our knowledge, canine clinical NDM-5 E. coli in Europe, and confirmed CPE transmission between dogs and humans have not been previously reported. The screening of veterinary Enterobacteriaceae isolates for carbapenem resistance is highly recommended.

A Serratia marcescens outbreak in a neonatal intensive care unit was successfully managed by rapid hospital hygiene interventions and screening

AIM

Serratia marcescens is a rare, but important, pathogen in hospital-acquired infections, especially in neonatal units. Outbreaks may cause significant mortality among neonates. This study describes how an outbreak of S. marcescens was handled in a neonatal intensive care unit in Finland in June 2015.

METHODS

Tampere University Hospital is the only hospital that offers intensive care for preterm neonates in the Pirkanmaa health district area in Finland. Between June 9, 2015 and June 29, 2015, seven neonates were screened positive for S. marcescens in the hospital. We examined the management and outcomes, including environmental sampling.

RESULTS

Two of the seven neonates developed a bloodstream infection, and one with S. marcescens sepsis died after six days of antibiotic treatment. The outbreak was rapidly managed with active hospital hygiene interventions, including strict hand hygiene, cleaning, patient screening, contact precautions and education. Environmental sampling was limited to one water tap and a ventilator, and the results were negative. The outbreak was contained within three weeks, and no further cases appeared. The screening of healthcare workers was not necessary.

CONCLUSION

A S. marcescens outbreak caused significant morbidity in neonates and one death. Rapid hospital hygiene interventions and patient screening effectively contained the outbreak.

Relapsing sepsis episodes of Escherichia coli with CTX-M ESBL or derepressed ampC genes in a patient with chronic autoimmune pancreatitis complicated by IgG4 hypergammaglobulinaemia

Bloodstream recurrent infections have been reported for a variety of opportunistic bacteria. These are often either catheter related or are caused by indwelling devices. A case of relapsing sepsis with two Escherichia coli strains carrying extended-spectrum β-lactamase and derepressed ampC genes is reported. The patient had seven episodes of bloodstream infections within 1 year and was diagnosed with chronic autoimmune pancreatitis and IgG4 hypergammaglobulinaemia. Abscesses were found in his spleen and pancreas cauda, which was finally resected. Relapses of bacteraemia with resistant enterobacteria should be considered during perioperative protection. Surgical removal of the infective focus could be curative.

High-throughput screening of colonization samples for methicillin-resistant Staphylococcus aureus

BACKGROUND

We present here the first application of 2-photon excited fluorescence detection (TPX) technology for the direct screening of clinical colonization samples for methicillin-resistant Staphylococcus aureus (MRSA).

METHODS

A total of 125 samples from 14 patients with previously identified MRSA carriage and 16 controls from low-prevalence settings were examined.

RESULTS

The results were compared to those obtained by both standard phenotypic and molecular methods. In identifying MRSA carriers, i.e. persons with at least 1 MRSA positive colonization sample by standard methods, the sensitivity of the TPX technique was 100%, the specificity 78%, the positive predictive value 75%, and the negative predictive value 100%. The TPX assay sensitivity per colonization sample was 89%, the specificity 93%, the positive predictive value 84%, and the negative predictive value 95%. The median time for a true-positive test result was 3 h and 26 min; negative test results are available after 13 h. The assay capacity was 48 samples per test run.

CONCLUSIONS

The TPX MRSA technique could provide early preliminary results for clinicians, while simultaneously functioning as a selective enrichment step for further conventional testing. Costs and workload associated with hospital infection control can be reduced using this high-throughput, point-of-care compatible methodology.

Bacterial and viral etiology of childhood diarrhea in Ouagadougou, Burkina Faso

BACKGROUND

Diarrhea is the most frequent health problem among children in developing countries. This study investigated the bacterial and viral etiology and related clinical and epidemiological factors in children with acute diarrhea in Ouagadougou, Burkina Faso.

METHODS

Stool specimens were collected from 283 children under 5 years of age visiting hospital due to acute diarrhea and from 60 healthy controls of similar age. Pathogens were investigated by using conventional culture techniques, PCR and immunochromatographic testing. Salmonella and Shigella strains were serotyped and their susceptibility to 23 antimicrobial agents was determined by the agar dilution method.

RESULTS

At least one pathogen was detected in 64% of the 283 patients and in 8% of the 60 controls (p < 0.001). Rotavirus was found in 30% of the patients, followed by diarrheagenic Escherichia coli (24%), Salmonella enterica ssp. enterica (9%), Shigella spp. (6%), adenovirus (5%) and Campylobacter spp. (2%). Multiple pathogens were found in 11% of the patients and in 2% of the controls (p = 0.028). Viruses were found mainly in children of ≤ 2 years of age, whereas bacteria were equally prevalent among all the age groups. Viral infections occurred mostly during the cool dry season and the bacterial infections during the rainy season. Fever (64%) and vomiting (61%) were the most common symptoms associated with diarrhea. Only one Salmonella strain was resistant to nalidixic acid and ciprofloxacin. Of the Shigella strains, one was resistant to nalidixic acid but 81% to trimethoprim- sulfamethoxazole, 63% to streptomycin and 50% to ampicillin. Most of all the other Salmonella and Shigella strains were sensitive to all antimicrobials tested.

CONCLUSION

Rotaviruses and diarrheal E. coli were the most predominant pathogens associated with acute diarrhea in Burkinabe children. Constant antimicrobial surveillance is warranted to observe for the emergence of enteric bacteria resistant to antimicrobials that are important in treatment also of severe infections.

Carbapenemase-producing Enterobacteriaceae in Finland: the first years (2008-11)

OBJECTIVES

Carbapenemase-producing Enterobacteriaceae (CPE) are becoming a global problem; they are often resistant to nearly all available antibiotics. Here we report details on all Finnish CPE isolates found until the end of 2011: carbapenemase genes, travel history and multilocus sequence typing (MLST) data.

METHODS

Enterobacteriaceae sent to the Antimicrobial Resistance Unit of the National Institute for Health and Welfare were tested for susceptibility to carbapenems, screened for carbapenemases by PCR and isolates with decreased susceptibility to carbapenems were tested for hydrolysis of imipenem. Carbapenemase-producing Escherichia coli and Klebsiella pneumoniae isolates were typed by MLST.

RESULTS

In all, 26 CPE strains were found from 25 patients: 10 with OXA-48-like enzymes, 5 with KPC, 4 with VIM, 3 with NDM, 3 with IMI/NMC-A and 1 with GES-14. The species were K. pneumoniae (n = 16), E. coli (n = 6), Enterobacter cloacae (n = 3) and Raoultella planticola (n = 1). Of the 25 patients, 18 had a known travel history/hospital transfer from abroad. Local spread/transmission was suspected in 2011, but there were no hospital outbreaks. The K. pneumoniae multilocus sequence types ST258, ST182, ST147, ST244, ST14, ST13, ST383, ST101 and ST15, and the E. coli sequence types ST38 and ST90 were found. Many of these are global epidemic clones.

CONCLUSIONS

CPE strains are increasingly found in Finland, but still at a very low prevalence.

Synthesis of methacrylate monomers with antibacterial effects against S. mutans

A series of polymerizable quaternary ammonium compounds were synthesized with the aim of using them as immobilized antibacterial agents in methacrylate dental composites, and their structures were characterized by FT-IR, ¹H-NMR, and ¹³C-NMR analysis. Their antibacterial activities against the oral bacterium Streptococcus mutans were evaluated in vitro by a Minimum Inhibitory Concentration test, and the results showed that 2-dimethyl-2-hexadecyl-1-methacryloxyethyl ammonium iodide (C16) had the highest antibacterial activity against S. mutans, and 2-dimethyl-2-pentyl-1-methacryloxyethyl ammonium iodide (C5) and 2-dimethyl-2-octyl-1-methacryloxyethyl ammonium iodide (C8) did not show any inhibition.

First isolations of KPC-2-carrying ST258 Klebsiella pneumoniae strains in Finland, June and August 2009

The first two Klebsiella pneumoniae carbapenemase-producing (KPC) type 2 strains carrying ST258 were detected in Finland in June and early August 2009. They were found colonising two patients transferred from the Mediterranean; one patient referred from a hospital in Greece where isolates were first found in 2007 and another from Italy where the first isolates have been described only very recently.