A Community Waterborne Salmonella Bovismorbificans Outbreak in Greece

BACKGROUND

In August 2022, the Hellenic National Public Health Organisation was notified about a gastroenteritis outbreak in town A in Southern Greece. Investigations aimed to identify the source and implement control measures.

METHODS

Case definition categories were used in a 1:3 case-control study. Cases and controls were interviewed about various exposures. Cases' stool samples were cultured on agar plates and characterised by serotyping, antimicrobial susceptibility testing and Pulse Field Gel Electrophoresis (PFGE). Environmental investigations included tap water sampling for microbiological and chemical analysis in town A and inspection of the water supply system.

RESULTS

We identified 33 cases (median age: 17 years). Tap water consumption was the only significant risk factor for gastroenteritis (OR = 5.46, 95% CI = 1.02-53.95). Salmonella (S.) Bovismorbificans isolated from eight stool and one tap water samples had identical PFGE profiles. No resistant isolates were identified. Residual chlorine levels were lower than the acceptable limits before and during the outbreak. We advised consumption of bottled water and adherence to strict hand hygiene rules until tap water was declared suitable for drinking.

CONCLUSIONS

Epidemiological and molecular data revealed a waterborne S. Bovismorbificans outbreak in town A. We recommend local water safety authorities to ensure that residual chlorine levels comply with the legislation towards water safety planning, to mitigate risks.

Meningococcal Antibiotic Resistance: Molecular Characterization of Isolates from Patients with Invasive Meningococcal Disease (IMD) in Greece

For effective case management and chemoprophylaxis of Invasive Meningococcal Disease (IMD), prompt antibiotic treatment is required. N. meningitidis is usually susceptible to antibiotics, but reduced susceptibility to penicillin, ciprofloxacin, and rifampicin is increasing worldwide, jeopardizing patients' outcome. We assessed, phenotypically and genotypically, the antimicrobial resistance patterns of 192 strains isolated from IMD cases from all over Greece during 2010-2021. Antimicrobial susceptibility to penicillin, rifampicin, and ciprofloxacin was determined using the E-test. All isolates were genotyped by Multilocus Sequence Typing (MLST). penA, rpoB, and gyrA genes were amplified by PCR and sequenced. Of the 192 isolates, 37% (72/192) were penicillin-susceptible/had increased exposure, and 11% (21/192) were penicillin-resistant. Among those, 40 penA alleles were identified; penA1, penA27, and penA3 were highly associated with susceptibility to penicillin; penA14, penA25, and penA22 related to reduced susceptibility to penicillin, while penA9, penA910, and penA295 had resistance to penicillin. Two ciprofloxacin-resistant isolates harbored the gyrA346 allele, while one rifampicin-resistant isolate harbored the rpoB5 allele. Resistance to ciprofloxacin and rifampicin remains rare. As Greece is one of the countries with high antimicrobial resistance, continued monitoring of antibiotic resistance is important to ensure timely detection of emerging resistance for treatment and prevention guidelines.

Postpartum bacteraemia outbreak due to Bacillus cereus in the delivery room

We report an outbreak Bacillus cereus causing postpartum bacteraemia in the maternity ward and delivery room. Spores transferred by the hands and gloves of the staff in the maternity ward contaminated equipment in these two areas.

Emergence and dissemination of a linezolid-resistant Staphylococcus capitis clone in Europe

Objectives

We investigated the epidemiological, clinical, microbiological and genetic characteristics of linezolid-resistant (LZR) Staphylococcus capitis isolates from French ICUs, and compared them with LZR S. capitis isolates from other European countries.

Methods

All LZR isolates were subjected to antimicrobial susceptibility testing (AST) and the presence of cfr and optrA genes as well as mutations in the 23S rRNA and ribosomal proteins were investigated using specific PCR with sequencing. The genetic relationship between isolates was investigated using PFGE and WGS. Epidemiological data concerning LZR S. capitis were collected retrospectively in French microbiology laboratories.

Results

Twenty-one LZR isolates were studied: 9 from France, 11 from Greece and 1 from Finland. All were resistant to methicillin and aminoglycosides. In addition, this unusual AST profile was identified in S. capitis isolates from seven French hospitals, and represented up to 12% of the S. capitis isolates in one centre. A G2576T mutation in 23S rRNA was identified in all isolates; cfr and optrA genes were absent. All isolates belonged to the same clone on the basis of their PFGE profiles, whatever their geographical origin. WGS found at most 212 SNPs between core genomes of the LZR isolates.

Conclusions

We identified and characterized an LZR S. capitis clone disseminated in three European countries, harbouring the same multiple resistance and a G2576T mutation in the 23S rRNA. The possible unrecognized wider distribution of this clone, belonging to a species classically regarded as a low-virulence skin colonizer, is of major concern not least because of the increasing use of oxazolidinones.

MRSA infections among patients in the emergency department: a European multicentre study

BACKGROUND

MRSA is a therapeutic concern worldwide, and a major agent of community-acquired skin and soft tissue infections (CA-SSTIs). While the US epidemiology of MRSA in CA-SSTIs is well described and reports the high prevalence of the USA300 clone, data on the European situation are lacking.

OBJECTIVES

To determine the prevalence and clonal characteristics of MRSA in CA-SSTIs in seven European emergency departments.

PATIENTS AND METHODS

From April to June 2015, patients presenting to the tertiary hospital emergency department with a Staphylococcus aureus CA-SSTI were prospectively enrolled. S. aureus isolates were characterized by antimicrobial susceptibility testing, detection of Panton-Valentine leucocidin encoding genes and spa-typing, MLST and/or DNA microarray.

RESULTS

Two-hundred and five cases of S. aureus-associated CA-SSTIs were included, comprising folliculitis, furuncles, abscesses, paronychia, impetigo, carbuncles and cellulitis. Of the 205 cases, we report an MRSA prevalence rate of 15.1%, with a north (0%) to south (29%) increasing gradient. Fifty-one isolates were Panton-Valentine leucocidin-positive (24.9%), whether MSSA or MRSA, with a heterogeneous distribution between countries. Clonal distribution of MSSA and MRSA showed high diversity, with no predominant circulating clone and no archetypical USA300 CA-MRSA clone.

CONCLUSIONS

This original prospective multicentre study highlights stark differences in European MRSA epidemiology compared with the USA, and that the USA300 CA-MRSA clone is not predominant among community-infected patients in Europe.

Pitfalls in the identification of Enterococcus species and the detection of vanA and vanB genes

The aims were to assess the performance of Vitek 2 in identifying enterococcal species and the implementation of GeneXpert(®) vanA/vanB PCR for the detection of vancomycin-resistant enterococci (VRE). Gram-positive cocci from clinical and environmental specimens (n = 431) suspicious of being enterococci by conventional methods were evaluated by Vitek 2. This system identified 296 Enterococcus faecium, 87 Enterococcus faecalis, 10 Enterococcus villorum, 9 Enterococcus gallinarum, 9 Enterococcus durans, 5 Enterococcus casseliflavus, 1 Enterococcus spp. and 14 isolates as Non-Enterococcus. All strains were submitted to pulsed field gel electrophoresis (PFGE) analysis showing 64 banding patterns. Representative strains from each banding pattern were further characterized to species level by 16S rDNA sequencing. The misidentification rate by Vitek 2 to species level among 429 molecularly identified enterococci was 6% (26 isolates). Additionally, 372 rectal swabs were obtained from critically ill patients. They were evaluated for the presence of VRE by ChromID VRE combined with in-house PCR vs GeneXpert(®) . GeneXpert(®) showed high (>92%) sensitivity, specificity, accuracy for vanA-positive Enterococcus detection, as well as, sensitivity and specificity for vanB-positive strains. Positive predictive value for detection of vanB-positive enterococci by GeneXpert(®) vanA/vanB was low (30%). GeneXpert(®) showed the same efficacy as ChromID VRE in detecting vanA-positive enterococci, but lower for vanB-gene detection.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study shows that even though the performance of Vitek 2 Advanced Expert System was good in identifying enterococci to species level, it is important to verify results by a molecular method when phenotypic findings are discordant with epidemiologic patterns. Furthermore, GeneXpert(®) vanA/vanB PCR and ChromID VRE combined with in-house PCR were applied in rectal samples for the detection of VRE colonization among critically ill patients. GeneXpert(®) showed an excellent performance in detecting vanA-positive enterococci, but false-positive results for vanB-gene detection render its application problematic in departments with high incidence of vanB-positive enterococci.

Toxoplasma gondii meningoencephalitis without cerebral MRI findings in a patient with ulcerative colitis under immunosuppressive treatment

Toxoplasmosis is the most common opportunistic infection of the central nervous system in immunosupressed patients. It is usually presented as a space-occupying lesion detected by cerebral computerized tomography or magnetic resonance imaging. The diffuse form of the disease (diffuse toxoplasmic meningoencephalitis) lacks the characteristic cerebral radiologic findings rendering pre-mortem diagnosis much more difficult. Herein, we describe a case of toxoplasmic menincoencephalitis, without evidence of cerebral space-occupying lesions, in a patient with ulcerative colitis under combined therapy with systemic glucocorticoids and azathioprine. Diagnosis was based on microscopic examination of cerebrospinal fluid (CSF) for the parasite, whereas, RT-PCR for Toxoplasma gondii was negative. Taking into consideration the limitations of molecular methods, investigation of the etiology of meningeal involvement in patients under immunosuppressive therapy presenting positive serology of previous T. gondii infection, should include microscopic examination of CSF for parasite presence.

Human Staphylococcus aureus lineages among Zoological Park residents in Greece

Staphylococcus aureus is a part of the microbiota flora in many animal species. The clonal spread of S. aureus among animals and personnel in a Zoological Park was investigated. Samples were collected from colonized and infected sites among 32 mammals, 11 birds and eight humans. The genes mecA, mecC, lukF/lukS-PV (encoding Panton-Valentine leukocidin, PVL) and tst (toxic shock syndrome toxin-1) were investigated by PCR. Clones were defined by Multilocus Sequence Typing (MLST), spa type and Pulsed-Field Gel Electrophoresis (PFGE). Seven S. aureus isolates were recovered from four animals and one from an employee. All were mecA, mecC and tst–negative, whereas, one carried the PVL genes and was isolated from an infected Squirrel monkey. Clonal analysis revealed the occurrence of seven STs, eight PFGE and five spa types including ones of human origin. Even though a variety of genotypes were identified among S. aureus strains colonizing zoo park residents, our results indicate that colonization with human lineages has indeed occurred.

Virulence factors among Staphylococcus lugdunensis are associated with infection sites and clonal spread

Staphylococcus lugdunensis has emerged as a significant human pathogen, with distinct clinical and microbiological characteristics. Our goal was to identify the virulence factors in S. lugdunensis recovered from infected patients of two Greek hospitals during a six-year period (2008-2013). A collection of 38 S. lugdunensis was tested for biofilm formation, antimicrobial susceptibility, clonal distribution, virulence factors (ica operon, fbl, atlL, vwbl, slush) and antibiotic resistance genes (mecA, ermC) carriage. Strains were classified into pulsotypes by pulsed-field gel electrophoresis (PFGE) of SmaI DNA digests. The majority (22) was isolated from skin and soft tissue infections (SSTIs), nine from deep-sited infections (DSIs), including three bacteraemias and seven from prosthetic device-associated infections (PDAIs). All isolates were oxacillin-susceptible, mecA-negative and fbl-positive. The highest resistance rate was detected for ampicillin (50%), followed by erythromycin and clindamycin (18.4%). Fourteen isolates (36.8%) produced biofilm, whereas 26/38 (68.4%) carried the ica operon. Biofilm formation was more frequent in isolates from PDAIs. Thirty-six strains (94.7%) carried atlL and 31 (81.6%) carried vwbl, whereas slush was detected in 15 (39.5%). PFGE revealed a low level of genetic diversity: strains were classified into seven pulsotypes, with two major clones (C: 22 and D: nine strains). Type C strains recovered from all infection sites prevailed in biofilm formation and ermC carriage, whereas type D strains associated with SSTIs and DSIs carried more frequently vwbl, slush or both genes. Despite susceptibility to antimicrobials, the clonal expansion and carriage of virulence factors, combined with biofilm-producing ability, render this species an important pathogen that should not be ignored.

Mycobacterium kansasii cutaneous infection in a patient with sarcoidosis treated with anti-TNF agents

We describe a Mycobacterium kansasii cutaneous infection that was diagnosed in a 52-year-old female patient with sarcoidosis receiving anti-TNF agents. The diagnosis was based on the positive culture of the foot ulcerative tissue. The isolation and identification of bacterium was based on phenotypic and molecular methods. Therapy and follow-up of the patient is discussed.

A 12-year survey of methicillin-resistant Staphylococcus aureus infections in Greece: ST80-IV epidemic?

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of both healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) infections. Severe MRSA infections have been associated with the virulence factor Panton-Valentine leukocidin (PVL). The aim of this study was to investigate susceptibility patterns, the presence of toxin genes, including that encoding PVL, and clonality among MRSA isolates collected from patients in Greece over a 12-year period. MRSA isolates were collected from January 2001 to December 2012 from six different hospitals. Antibiotic susceptibility was determined with the disk diffusion method and the Etest. The presence of the toxic shock syndrome toxin-1 gene (tst), the enterotoxin gene cluster (egc) and the PVL gene was tested with PCR. The genotypic characteristics of the strains were analysed by SCCmec and agr typing, and clonality was determined with pulsed-field gel electrophoresis and multilocus sequence typing. An increasing rate of MRSA among S. aureus infections was detected up to 2008. The majority of PVL-positive MRSA isolates belonged to a single clone, sequence type (ST)80-IV, which was disseminated both in the community and in hospitals, especially during the warmest months of the year. Carriage of tst was associated with ST30-IV, whereas egc was distributed in different clones. CA-MRSA isolates were recovered mainly from skin and soft tissue infections, whereas HA-MRSA isolates were associated with surgical and wound infections. During the period 2001-2012, ST80-IV predominated in the community and infiltrated the hospital settings in Greece, successfully replacing other PVL-positive clones. The predominance of ST239-III in HA-MRSA infections was constant, whereas new clones have also emerged. Polyclonality was statistically significantly higher among CA-MRSA isolates and isolates from adult patients.

Performance of chromID® CARBA medium for carbapenemases-producing Enterobacteriaceae detection during rectal screening

Chromogenic chromID® CARBA medium was compared with CDC method and MacConkey agar with imipenem for its performance in detecting carbapenemase-producing Enterobacteriaceae (CPE) during a faecal screening surveillance program. Double rectal swabs were collected from patients hospitalized in the ICU. One swab was inoculated onto the solid media chromID® CARBA and MacConkey agar with imipenem, while the other was tested according to CDC protocol. Suspected colonies from all procedures were identified to species level and tested for their susceptibility to carbapenems by phenotypic tests. All carbapenem non-susceptible isolates were tested by the modified Hodge test (MHT) and synergy tests. Positive results were confirmed by PCR testing for carbapenemase gene detection. Performance of all three procedures applied was statistically analyzed as compared to MHT and PCR results for the presence of carbapenemase-encoding genes. Out of 177 rectal samples tested, 86 samples were found to contain one or more CPE verified by molecular detection of carbapenemase encoding genes among isolated Enterobacteriaceae. Sensitivity of chromID® CARBA was 96.5 % in clinical samples. Specificity was 91.2 % at the reading level and 100.0 % after Gram staining. chromID® CARBA performed with high accuracy among the phenotypic methods applied, giving early results.

Modified directly observed treatment for tuberculosis versus self-administered therapy: an observational study in rural Greece

INTRODUCTION

Directly Observed Treatment (DOT) is the key element of DOTS (directly observed treatment, short course), part of the internationally recommended control strategy for tuberculosis (TB). The evaluation of DOT has not been widely evaluated in rural areas in developed settings. The aim of this pilot study was to evaluate a modified DOT program (MDOT) by a general practitioner (GP) in a rural area of southwest Greece, where there is substantial underreporting of TB cases.

METHODS

Thirteen new TB cases with 30 close contacts were compared with 41 past-treated TB subjects (controls) with 111 close contacts in this observational, case-control study. Home visits by a GP were conducted and comparison of various data (laboratory findings, treatment outcomes, questionnaire-based parameters, on-site recorded conditions) was performed in both newly detected pulmonary TB cases and previously treated TB cases managed without DOT intervention.

RESULTS

MDOT by GP implementation revealed that 11 cases (84.6%) were successfully treated, one (7.7%) case died, and one (7.7%) was lost to follow up. None of the close contacts of new TB cases was infected with active TB, while 6.3% of previously-treated TB subjects were infected with active TB and had to receive a complete anti-TB regimen. Chemoprophylaxis was administered to 13.3% of close contacts of new cases; whereas 12.6% of close contacts of previously-treated patients received chemoprophylaxis.

CONCLUSION

This pilot study revealed that a GP is able to implement a program based on DOT resulting in high treatment adherence and prevention of TB compared with the conventional self-administration of treatment.

The combined effect of surface chemistry and flow conditions on Staphylococcus epidermidis adhesion and ica operon expression

The assessment of biomaterial susceptibility to infection relies mainly on the analysis of macroscopic bacterial responses to material interactions, usually under static conditions. However, new technologies permit a more profound understanding of the molecular basis of bacteria-biomaterial interactions. In this study, we combine both conventional phenotypic analysis - using confocal microscopy - and genotypic analysis - using the relative reverse transcription polymerase chain reaction (RT-PCR) - to examine the interaction of bacteria with OH- and CH3-terminated glass surfaces, under dynamic flow conditions. Bacterial adhesion, as well as slime production and biofilm formation, was much higher on the CH3-terminated than on the OH-terminated glass - for four Staphylococcus epidermidis strains. This was in agreement with the icaA and icaD gene expression results that showed increased expression for the bacteria adhering to the CH3-terminated substrate, especially under the higher shear rate. Therefore, the combined effect of the surface chemistry and shear significantly influence the adhesion and phenotype of interacting bacterial cells, while there are putative links between phenotypic responses to bacteria-material interactions and gene-expression profile alterations. This indicates that analysis of gene expression not only can greatly refine our knowledge of bacteria-material interactions, but also yield novel biomarkers for potential use in biocompatibility assessment.

Effect of glutamine on intestinal mucosal integrity and bacterial translocation after abdominal radiation

This study evaluates the effect of oral glutamine on intestinal mucosal integrity and bacterial translocation in rats. 80 animals were randomised into four groups: group 1 (chow diet and water), group 2 (chow diet and glutamine 3%), group 3 (radiation, chow diet and water), group 4 (radiation, chow diet and glutamine 3%). Groups 1 and 2 were fed for 5 days, then sacrificed. Groups 3 and 4 were fed for 12 days, irradiated on the 5th day and sacrificed on 1st, 3rd and 7th post-radiation days. Cultures from the mesenteric lymph nodes (MLN), portal vein (PV) and aorta (A) were taken and two tissue samples were also taken from the terminal ileum for light and electron microscopic examination. In non-radiated rats glutamine did not alter the histologic parameters of villous height (VH), mitoses per crypt (M/C) and muscle thickness (MT). Group 3 rats had severe mucosal damage associated with a significant decrease of VH (p < 0.0001) and M/C (p < 0.01) on 1st and 3rd post-radiation days respectively. In contrast, group 4 rats maintained their mucosal structure and had a significant increase of VH and M/C (p < 0.0001) on post-radiation days 1 and 3. Bacterial translocation in MLN was 87.5% (p < 0.002) and 75% (p < 0.04) on 1st and 3rd post-radiation days respectively in group 3, and fell significantly to 12.5% (p < 0.002) in group 4. The data demonstrate that glutamine helps maintain the integrity of the intestinal mucosa and thereby reduces the incidence of bacterial translocation following abdominal irradiation.

Methicillin-resistant Staphylococcus aureus nasal carriage among healthy employees of the Hellenic Air Force

The prevalence of methicillin-resistant Staphylococcus aureus nasal carriage among 959 healthy employees of the Hellenic Air Force was investigated from November 2004 to October 2005. Nine participants were found to be colonised by methicillin-resistant Staphylococcus aureus (MRSA) (SCCmec type IV). Eight of the MRSA isolates were PVL-negative and belonged to ST30 by MLST, while the remaining one isolate was PVL-positive and classified as ST-80.

Community-associated Staphylococcus aureus infections and nasal carriage among children: molecular microbial data and clinical characteristics

An increasing number of infections caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) carrying the Panton-Valentine leukocidin (PVL) genes was recently identified in Greece. In the present study, 170 patients with S. aureus infections and 123 uninfected children (<15 years old) who had been tested for nasal carriage were evaluated during a 2-year period. The MecA, PVL and superantigen family genes, and MRSA clones, were investigated by molecular methods. Sites of infection and laboratory findings for patients were recorded. The results were compared and statistically analysed. Among 123 uninfected children 73 (59%) carried S. aureus, including four MRSA strains. Of these, three MRSA and three methicillin-sensitive S. aureus (MSSA) strains were PVL-positive (p <0.0001). Ninety-six patients (96/170) exhibited skin and soft-tissue infections (SSTIs), and 74 exhibited invasive infections. The incidence of staphylococcal infections increased during July to September each year. In total, 110 S. aureus isolates were PVL-positive (81 from SSTIs and 29 from invasive infections, p <0.0001). Ninety-nine out of 106 MRSA (93%) isolates from 170 patients carried the PVL genes (p <0.0001); 97 belonged to the clonal complex CC80. Leukocyte and polymorphonuclear cell counts were higher among children with MRSA infections (p <0.005). MSSA predominated among patients with invasive infections (43/74), and carried mainly genes of the superantigen family. Children <5 years of age showed a higher risk of MRSA infection. The present study demonstrates that infections due to PVL-positive CA-MRSA spread easily among children, and SSTIs can lead to invasive infections. Nasal colonization may be an additional factor contributing to the emergence of CA-MRSA.

In vitro activity of daptomycin against Gram-positive cocci: the first multicentre study in Greece

A total of 10420 Gram-positive cocci (including staphylococci, enterococci and various groups of streptococci) collected from clinically significant specimens in ten Greek hospitals during 2006--2007 were tested for their susceptibility to daptomycin. The minimum inhibitory concentration (MIC) was determined by the broth microdilution method. Daptomycin demonstrated very high activity against Enterococcus faecalis (MIC at which 50% of the isolates were inhibited (MIC50) = 1mg/L and MIC at which 90% of the isolates were inhibited (MIC90) = 1.36 mg/L), Enterococcus faecium (MIC50 = 1.36 mg/L and MIC90 = 1.90 mg/L), Streptococcus pyogenes (MIC50 = 0.12 mg/L and MIC90 = 0.50mg/L), Streptococcus agalactiae (MIC50 = 0.09 mg/L and MIC90 = 0.12 mg/L), Streptococcus pneumoniae (MIC50 = 0.24 mg/L and MIC90 = 0.5 mg/L) and viridans group streptococci (MIC50 = 0.50 mg/L and MIC90 = 0.89 mg/L). Resistance to linezolid and vancomycin for enterococci and to penicillin for streptococci appears to be independent of reduced susceptibility to daptomycin. On the other hand, daptomycin was also active against meticillin-resistant Staphylococcus aureus (MIC50 = 0.44 mg/L and MIC90 = 0.78 mg/L) and meticillin-resistant coagulase-negative staphylococci (MIC50 = 0.24 mg/L and MIC90 = 0.44 mg/L); however, 0.9% of the staphylococci tested had an MIC > 1mg/L, which is the Clinical and Laboratory Standards Institute breakpoint proposed for susceptibility. For all tested organism groups, resistance to daptomycin was not associated with glycopeptide resistance.

Absolute and relative real-time PCR in the quantification of tst gene expression among methicillin-resistant Staphylococcus aureus: evaluation by two mathematical models

AIM

Absolute and relative quantitative real-time reverse transcriptase polymerase chain reaction (RT-PCR) by the use of two mathematical models were applied in order to study the expression of tst gene encoding the toxic shock syndrome toxin-1 (TSST-1), among methicillin-resistant Staphylococcus aureus (MRSA).

METHODS AND RESULTS

Thirteen epidemic MRSA belonging to different clones and carrying a variety of toxin genes were selected. tst gene expression was achieved by using absolute and relative quantitative real-time RT-PCR and the SYBR Green I. Absolute RT-PCR showed a statistically significant higher level of tst expression among strains isolated from soft tissue infections. Relative quantification was performed in relation to 23S rRNA expression by the application of two mathematical models, the 2(-DeltaDeltaCt) and the Pfaffl analysis methods.

CONCLUSIONS

tst gene expression was best calculated by the relative real-time RT-PCR analysis applying the Pfaffl analysis method, taking into account the reactions' efficiencies. Level of tst expression was related to patients' infection and did not depend on the MRSA genetic profile.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results indicate that the application of the Pfaffl analysis method in the evaluation of relative real-time RT-PCR is more adequate.

Methicillin-resistant Staphylococcus aureus producing Panton–Valentine leukocidin as a cause of acute osteomyelitis in children

Staphylococcus aureus was identified as the cause of acute childhood osteomyelitis in 19 patients. A single clone of community-acquired methicillin-resistant S. aureus (MRSA) carrying the type IV mecA staphylococcal cassette chromosome and the Panton-Valentine leukocidin (PVL) genes was isolated from five patients. Among the remaining 14 patients, two methicillin-sensitive S. aureus (MSSA) isolates were PVL-positive. The maximal erythrocyte sedimentation rate and C-reactive protein values, and the time required for normalisation, were significantly different in patients with PVL-positive strains (MRSA and MSSA), suggesting that the production of PVL is an important factor that contributes to the course of the disease.

Comparison of two commercial methods with PCR restriction fragment length polymorphism of the tuf gene in the identification of coagulase-negative staphylococci

AIMS

Two commercial methods for the identification of coagulase-negative staphylococci (CNS) were compared with the restriction fragment length polymorphism (RFLP) of the amplified tuf gene, which served as the reference method.

METHODS AND RESULTS

One hundred and forty-five CNS were evaluated using the API 32 Staph ID and the Crystal GP/ID BBL systems. The PCR-RFLP of the tuf gene served as the reference method. The APIStaph and the GP/ID BBL had an overall rate of agreement with the molecular method of 58.6% and 46.2% respectively, with the inability of the GP/ID BBL to characterize 11.7% of the isolates. The APIStaph showed higher sensitivity and better agreement than the GP/ID BBL with the PCR-RFLP, except for Staphylococcus hominis and Staphylococcus capitis.

CONCLUSIONS

Neither of the commercial systems was as reliable as the PCR-RFLP method for identifying isolates of CNS. Overall the APIStaph had better agreement with the PCR-RFLP than the GP/ID system.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results indicate that the PCR-RFLP method is more reliable than the two commercial systems tested, suggesting that it is more reliable for routinely identifying CNS.

Clonality of slime-producing methicillin-resistant coagulase-negative staphylococci disseminated in the neonatal intensive care unit of a university hospital

Methicillin-resistant coagulase-negative staphylococci (MR-CNS) (n = 132), isolated from pre-term neonates, were analysed to determine their antibiotic resistance patterns, clonal distribution, biofilm production and the presence of the ica operon. All MR-CNS were multiresistant, and 89% produced slime. A major clone was identified (77 isolates) among 115 Staphylococcus epidermidis isolates. Ten of 16 Staphylococcus haemolyticus isolates also belonged to a single clone. Most (80%) slime-positive isolates possessed all the ica genes tested, while the remaining 23 (20%) had a variety of gene combinations. The entire ica cluster was detected in three of 15 slime-negative isolates. One major and two minor slime-positive, multiresistant MR-CNS clones had disseminated among hospitalised pre-term neonates.

Adhesion of slime producing Staphylococcus epidermidis strains to PVC and diamond-like carbon/silver/fluorinated coatings

Staphylococcus epidermidis has emerged as a pathogen associated with infections of implanted medical devices. Bacterial adhesion is a crucial step in infection on biomaterial surfaces. To quantitatively determine the relationship between poly (vinyl chloride) (PVC) surface properties and bacterial adhesion, we have compared attachment of slime-producing S. epidermidis strains on PVC and various coatings under flow conditions. Bacterial adhesion and colonization was quantified by counting the viable organisms on the adherent surface as well as by scanning electron microscopy, epifluorescence microscopy and atomic force microscopy. Fluorination of the PVC surface encourages S. epidermidis adhesion whereas; diamond-like carbon (DLC) and especially silver (Ag) coatings seem to inhibit its adhesion. In most materials, the number of adherent bacteria decreased with the increase of shear rate. These results indicate that bacterial adhesion is influenced by the chemical properties of the polymeric surfaces, the surface roughness and the associated flow conditions.

Comparison of the manual Mycobacteria Growth Indicator tube and the Etest with the method of proportion for susceptibility testing of Mycobacterium tuberculosis

BACKGROUND

Clinical microbiology laboratories should provide reliable results on susceptibility testing of Mycobacterium tuberculosis to different agents.

METHODS

The manual Mycobacteria Growth Indicator Tube (MGIT) and Etest were compared to the method of proportion (MOP) for susceptibility testing of 88 clinical isolates of M. tuberculosis against isoniazid (INH), rifampin (RIF), streptomycin (STR) and ethambutol (EMB). Isolates were recovered from different patients and were identified at species level by PCR and hybridization.

RESULTS

Resistance to INH was detected in 20.5, 29.5 and 12.5% of the isolates, followed by STR resistance (19.3, 26.1 and 1.1%), RIF (9.1, 4.5 and 5.7%) and EMB (2.3, 11.4 and 2.3%) by the MOP, MGIT and Etest, respectively. Sensitivity of the manual MGIT ranged from 37.5% for RIF resistance to 100% for EMB, while Etest sensitivity ranged from 5.9% for STR to 62.5% for RIF.

CONCLUSIONS

MOP remains the method of choice, with the manual MGIT showing superior sensitivity at detecting resistance to INH, STR and EMB compared to the Etest.

Spread of Staphylococcus aureus clinical isolates carrying Panton-Valentine leukocidin genes during a 3-year period in Greece

Three collections of Staphylococcus aureus isolates (n = 1,058) were investigated to assess the spread of Panton-Valentine leukocidin (PVL)-producing strains in Greece and their association with skin and soft-tissue infections (SSTIs). The isolates were collected during 2001-2003 from inpatients and outpatients with invasive infections in two distinct geographical areas. Clonal types were identified according to their ClaI-mecA::ClaI-Tn554::pulsed-field gel electrophoresis patterns, and the presence of the lukS-PV and lukF-PV genes was assessed by PCR. In total, 287 (27%) S. aureus isolates carried the PVL genes: 45% of methicillin-resistant S. aureus (MRSA) and 12% of methicillin-sensitive S. aureus (MSSA). All the PVL-positive MRSA isolates belonged to a single clone that was disseminated in the community and hospitals. The PVL-positive MSSA isolates were polyclonal, with 14 of 65 isolates being associated with hospital-acquired infections. The community-acquired isolates were from SSTIs, while the hospital-acquired isolates were associated with surgical wound infections, especially those involving prosthetic devices. Thus, a unique clone of PVL-positive MRSA has spread in both the community and the hospital setting in Greece, and has replaced older clonal types.

Twenty-four-hour heart rate and blood pressure are additive markers of left ventricular mass in hypertensive subjects

BACKGROUND

We investigated whether mean heart rate (HR(24)) and blood pressure (BP) parameters during 24-h ambulatory BP monitoring (ABP) are independent or additive markers of left ventricular (LV) mass in subjects with newly diagnosed, untreated hypertension.

METHODS

A total of 250 patients (40% women, 60% men; mean age 59.6 +/- 11 years) with essential hypertension who were attending the outpatient Hypertension Unit were studied. All patients underwent 24-h ABP and HR monitoring as well as echocardiography for assessment of left ventricular (LV) dimensions and function.

RESULTS

A decreasing HR24 or increasing ABP parameters (ie, systolic, diastolic, mean BP, and pulse pressure) were associated with increasing LV mass (P < .001) and wall thickness (P < .01). In multivariate analysis, after adjusting for age, gender, body surface area, body mass index, hematocrit, glucose, cholesterol, smoking, and each of the measured ABP parameters separately, decreasing HR24 was independently related to increasing LV mass in addition to ABP and body size parameters (P < .001). The addition of HR24 in different multivariate models for prediction of LV mass significantly increased the adjusted model r2 (range of r2 change: 0.039 to 0.064, P for change <.05). Decreasing HR24 or HR during daytime (6 am to 10 pm) was associated with a higher likelihood of LV hypertrophy in addition to ABP parameters (adjusted odds ratio 0.92 (CI 0.87 to 0.98), per 1 beat/min greater HR24 P = .002 and 0.93 (CI: 0.87 to 0.98), per 1 beat/min greater HR in the daytime P = .017).

CONCLUSION

The 24-h HR and BP during ABP are independent and additive markers of increased LV mass in untreated hypertensive individuals.

Sensitivity of the Cobas Amplicor system for detection of Mycobacterium tuberculosis in respiratory and extrapulmonary specimens

The Cobas Amplicor PCR system (CA-PCR) was compared with culture and staining for acid-fast bacilli (AFB) for the early detection of Mycobacterium tuberculosis in respiratory clinical specimens and otherwise normal sterile body fluids. The sensitivity, specificity and positive and negative predictive values of CA-PCR were determined with AFB-positive and AFB-negative specimens. The sensitivity of CA-PCR ranged from 73.6% to 100% for AFB-positive samples, while sputa collected after bronchoscopy were the most useful specimens, with 70% sensitivity and 98.6% specificity among the AFB-negative samples.

Time Rate of Blood Pressure Variation Is Associated With Increased Common Carotid Artery Intima-Media Thickness

The extent of target-organ damage has been positively associated with the magnitude of blood pressure (BP) variability in essential hypertension. However, the clinical implications of the rate of BP changes have never been investigated. We evaluated the association between the rate of systolic BP (SBP) variation derived from ambulatory BP monitoring (ABPM) data analysis and the extent of common carotid artery (CCA) intima-media thickness (IMT) in normotensive (n=280) and in uncomplicated hypertensive subjects (n=234). The 24-hour rate of SBP variation was significantly ( P <0.001) higher in hypertensive (0.608 mm Hg/min; 95% confidence interval [CI], 0.595 to 0.622) than in normotensive individuals (0.567 mm Hg/min; 95% CI, 0.555 to 0.578), even after adjusting for baseline characteristics, day–night BP changes, 24-hour heart rate (HR), SBP, and HR variability. In the entire group of patients, multiple linear regression models revealed independent determinants of CCA-IMT in the following rank order: age ( P <0.001), 24-hour rate of SBP variation ( P <0.001), male gender ( P =0.004), cholesterol ( P =0.009), and smoking ( P =0.014). A 0.1 mm Hg/min increase in the 24-hour rate of SBP variation was associated to an increment of 0.029 mm (95% CI, 0.018 to 0.040) in CCA-IMT independent of BP and HR levels, BP and HR variability, and dipping status. The rate of SBP variation during the morning BP surge correlated independently ( P <0.001) to larger CCA-IMT values after adjustment for baseline characteristics and other ABPM parameters. Thus, the rate of BP fluctuations is greater in hypertensive patients and correlates to increased CCA-IMT. This finding indicates that steeper BP variations may produce a greater stress on the vessel wall and consequently result in medial hypertrophy of the large arteries.

The emergence of glycopeptide-resistant Enterococcus faecium in a university hospital in southwestern Greece

BACKGROUND

Enterococci and especially glycopeptide-resistant strains (GRE) are widely distributed in the hospital environment, by acquiring resistance determinants and virulence factors.

METHODS

The study included 48 GRE isolated during a 1-year period from different inpatients in a tertiary hospital in southwestern Greece. Antibiotic susceptibility was determined by the Etest, and the presence of resistance and virulence genes was shown by PCR. Clonal types were identified by pulsed-field gel electrophoresis of SmaI DNA digests.

RESULTS

All GRE were multi-resistant of the VanA phenotype, verified by the detection of the gene by PCR. Two major clones were distributed in all hospital wards. The majority of the strains (46 of 48) harbored the esp gene, while 27 GRE expressed also the gelE and/or as genes.

CONCLUSIONS

The spread of two clones expressing the vanA gene and virulence factors were responsible for the emergence of GRE in the University Hospital of Patras.