Risk factors for methicillin resistant Staphylococcus aureus: a multi-laboratory study

European hospitals as source of multidrug-resistant bacteria: analysis of travellers screened in Finland after hospitalization abroad

BACKGROUND

As hospitals have a high prevalence of multidrug-resistant organisms (MDRO), hospitalization abroad indicates for travellers an increased risk of acquiring MDRO-and carrying the strains home. Antimicrobial resistance (AMR) rates are highest in the (sub)tropics, whereas Europe is considered a lower risk region. Since AMR prevalences vary within Europe, we aimed to gather country-specific data on the risks for hospitalized travellers.

METHODS

At hospitals of the Helsinki and Uusimaa district in Finland, patients hospitalized abroad over the past 12 months are systematically screened for methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (ESBL-PE), carbapenemase-producing bacteria and vancomycin-resistant Enterococcus spp. (VRE). Among patients screened 2010-19, we selected those hospitalized in Europe, recorded their MDRO findings, infections and mortality, and analysed MDRO-associated risk factors.

RESULTS

Of the 1772 patients treated in 41 European countries, 16.6% (295) carried MDRO, 12.5% (221) ESBL-PE, 7.8% (138) solely ESBL-E. coli, 2.6% (46) MRSA, 2.2% (30) of those screened VRE and 2.2% (39) carbapenem-resistant Gram-negatives. Among those colonized, 9.8% (29) had symptomatic MDRO infections and 0.3% (one) died. Colonization was most frequently recorded for those treated in eastern and southern Europe, with Bulgaria, Cyprus and the Russian Federation scoring highest. MDRO colonization was associated with antibiotic treatment and showed a negative correlation with time from discharge to screening.

CONCLUSIONS

After hospitalization in European countries, ESBL-PE carriage was relatively common (12.5%), while other MDROs proved less frequent (<5%). Antibiotic treatment and short time since hospitalization abroad increased the risk of MDRO colonization. Clear differences between countries and regions were revealed, with highest rates in the east and the south.

Staphylococcus aureus with inducible clindamycin resistance and methicillin resistance in a tertiary hospital in Nepal

Background

Staphylococcus aureus is a global public health issue in both community and hospital settings. Management of methicillin-resistant S. aureus (MRSA) infections are tough owing to its resistance to many antibiotics. Macrolide-lincosamide-streptogramin B (MLSB) antibiotics are commonly used for the management of MRSA. This study was aimed to determine the occurrence of inducible clindamycin- and methicillin-resistant S. aureus at a tertiary care hospital in Kathmandu, Nepal.

Methods

A total of 1027 clinical samples were processed following standard laboratory procedures and antibiotic susceptibility testing of S. aureus was performed by disc diffusion method. MRSA isolates were detected phenotypically using cefoxitin disc, and inducible clindamycin resistance was detected phenotypically using the D-zone test.

Results

Of 1027 samples, 321 (31.2%) were culture positive, of which 38 (11.8%) were S. aureus. All S. aureus isolates were susceptible to vancomycin, and 25 (67%) of S. aureus isolates were multidrug-resistant. Similarly, 15 (39.5%) of S. aureus were MRSA and 14 (36.5%) were inducible clindamycin-resistant phenotypes.

Conclusion

Inducible clindamycin and methicillin resistance were common in S. aureus. This emphasizes that the methicillin resistance test and the D-zone test should be incorporated into the routine antibiotic susceptibility testing in hospital settings.

Place in Therapy of the Newly Available Armamentarium for Multi-Drug-Resistant Gram-Negative Pathogens: Proposal of a Prescription Algorithm

The worldwide propagation of antimicrobial resistance represents one of the biggest threats to global health and development. Multi-drug-resistant organisms (MDROs), including carbapenem-resistant non-fermenting Gram-negatives and Enterobacterales, present a heterogeneous and mutating spread. Infections by MDRO are often associated with an unfavorable outcome, especially among critically ill populations. The polymyxins represented the backbone of antibiotic regimens for Gram-negative MDROs in recent decades, but their use presents multiple pitfalls. Luckily, new agents with potent activity against MDROs have become available in recent times and more are yet to come. Now, we have the duty to make the best use of these new therapeutic tools in order not to prematurely compromise their effectiveness and at the same time improve patients’ outcomes. We reviewed the current literature on ceftazidime/avibactam, meropenem/vaborbactam and cefiderocol, focusing on antimicrobial spectrum, on the prevalence and mechanisms of resistance development and on the main in vitro and clinical experiences available so far. Subsequently, we performed a step-by-step construction of a speculative algorithm for a reasoned prescription of these new antibiotics, contemplating both empirical and targeted use. Attention was specifically posed on patients with life-risk conditions and in settings with elevated prevalence of MDRO.

Fatores associados à infecção por Staphylococcus aureus resistente à meticilina em unidade de terapia intensiva

OBJECTIVE

To identify factors associated with methicillin-resistant Staphylococcus aureus (MRSA) infection in adult patients admitted to the Intensive Care Unit (ICU), and to compare them with a control group.

METHODS

Retrospective case-control study carried out in an adult ICU, from January 2015 to June 2017, with 61 patients who developed methicillin-resistant Staphylococcus aureus infection and the same number of control patients.

RESULTS

Most participants were male 65 (60.6%), with a neurological diagnosis 43 (35.2%) and hypertensive 61 (50.0%). In the comparison of the groups, there was a statistically significant difference in relation to mechanical ventilation (p=0.0107), tracheostomy (p=0.0083), death (p=0.0401), urinary catheter (p=0.0420), length of stay (p<0.0001) and severity (p=0.0003). The main factors associated with methicillin-resistant Staphylococcus aureus infection were: severity (OR= 65.69; CI=3.726-4.808; p=0.0018), use of antimicrobials (OR= 0.047;CI=0.028-0.122;p=0.0024), length of stay (OR=1.19; CI=0.952-1.031; p=0.0285).

CONCLUSION

methicillin-resistant Staphylococcus aureus infection is multifactorial and has been associated with length of stay and severity. Use of antimicrobials was a protective factor.

Fluoroquinolone resistance in Escherichia coli isolates after exposure to non-fluoroquinolone antibiotics: a retrospective case-control study

OBJECTIVES

To investigate whether prior exposure to non-fluoroquinolone antibiotics increases the risk of fluoroquinolone resistance in Escherichia coli.

METHODS

This was a secondary analysis of data collected retrospectively in a case-control study linking microbiological test results (isolated bacteria and their susceptibility) of urine samples routinely collected from primary, secondary and tertiary care patients in Belgium with information on prior antibiotic use at the patient level up to 1 year previously.

RESULTS

In urine samples from 6125 patients, 7204 E. coli isolates were retrieved [1949 fluoroquinolone-resistant isolates (cases) and 5255 fluoroquinolone-susceptible isolates (controls)]. After adjusting for potential confounders (including fluoroquinolone use) and correcting for multiple testing there were lower odds of fluoroquinolone resistance in E. coli isolates after exposure to cefazolin (OR = 0.65; 95% CI = 0.52-0.81; P = 0.00014) and higher odds after exposure to trimethoprim/sulfamethoxazole (OR = 1.56; 95% CI = 1.23-1.97; P =0.00020) or nitrofurantoin (OR = 1.50; 95% CI = 1.23-1.84; P =0.000083). A sensitivity analysis excluding samples with antibiotic use during the 6 months prior to the sampling date confirmed the higher odds of fluoroquinolone resistance after exposure to trimethoprim/sulfamethoxazole and nitrofurantoin.

CONCLUSIONS

Assuming no residual confounding or other biases, this study suggests that exposure to non-fluoroquinolone antibiotics, i.e. trimethoprim/sulfamethoxazole and nitrofurantoin, might be causally related to fluoroquinolone resistance in E. coli isolates from urinary samples. Future prospective research is needed to confirm non-fluoroquinolone antibiotics as potential drivers of fluoroquinolone resistance.

Resistance Profiles of Staphylococcus aureus and Immunological Status in Pregnant Women at Bafang, West Region of Cameroon: A Cross-Sectional Study

Background

Staphylococcus aureus, a facultative aero-anaerobic Gram-positive coccus typically considered normal flora in the human gastrointestinal tract, have increasingly become a major cause of healthcare-associated infections over the past decade. This study aimed to evaluate the changes in immune factors in pregnant women colonized by S. aureus in the town of Bafang, West Region of Cameroon.

Methods

A cross-sectional study was carried in antenatal care unit in various health center in Bafang. S. aureus were isolated in stools using specific bacterial culture media. Antimicrobial susceptibility test was carried out using disk diffusion method. Blood was used to measure CD3, CD4 and CD8 T-cell lymphocyte counts, white blood cell count, high sensitivity C-reactive protein (hs-CRP) and interleukin-6 measurement using flow cytometry, optical detection and the ELISA solid phase direct sandwich method, respectively.

Results

Out of the 169 patients studied, 76.30% patients were pregnant women and 23.70% were non-pregnant women. S. aureus were isolated in 70.41% participants that is, 78.15% in pregnant and 21.85% in non-pregnant women. The mean age was significantly higher in non-pregnant women (29.38 ± 7.685 years) compared to pregnant women (25.55 ± 5.521 years). CD4 T-cell (574.80 ± 165.94; 754.03 ± 162.28, p < 0.001), were significantly lower in pregnant than non-pregnant women respectively, contrary for CD8 T-cell (333.86 ± 233.04; 250.40 ± 227.75, p = 0.043). S. aureus were significantly more isolated in pregnant women with a CD4 T-cell count between 410 and 625 cells/µl (p < 0.001). S. aureus were more susceptible to imipenem (91.40%), (100%); ciprofloxacin (65.59%), (69.44%); amikacin (96.77%), (100%) and resistant to chloramphenicol (78.49%), doxycycline (64.52%) and cefotaxime (51.61%) in pregnant women. Staphylococcus aureus showed a significant increased multidrug resistant (MDR) and methicillin-resistant S. aureus (MRSA) phenotypes in pregnant compared to non-pregnant women (p < 0.05).

Conclusion

The present study revealed that, Staphylococcus aureus, including resistant phenotypes should be considered in pregnant women to improve their health care.

Methicillin-resistant Staphylococcus aureus in Intensive Care Unit Setting of India: A Review of Clinical Burden, Patterns of Prevalence, Preventive Measures, and Future Strategies

Aim

The aim of this review article is not only to analyze the clinical burden of methicillin-resistant Staphylococcus aureus (MRSA) in intensive care unit (ICU) setting of India, along with the patterns of prevalence and its prevention measures, but also to focus on the new anti-MRSA research molecules which are in late stage of clinical development.

Background

Methicillin resistance is reported to be present in 13–47% of Staphylococcus aureus infections in India. Therapeutic options to combat MRSA are becoming less, because of emerging resistance to multiple classes of antibiotics. Intensive care units are the harbinger of multidrug-resistant organisms including MRSA and are responsible for its spread within the hospital. The emergence of MRSA in ICUs is associated with poor clinical outcomes, high morbidity, mortality, and escalating treatment costs. There is an urgency to bolster the antibiotic pipeline targeting MRSA. The research efforts for antibiotic development need to match with the pace of emergence of resistance, and new antibiotics are needed to control the impending threat of untreatable MRSA infections.

Review results

Fortunately, several potential antibiotic agents are in the pipeline and the future of MRSA management appears reassuring.

Clinical significance

The authors believe that this knowledge may help form the basis for strategic allocation of current healthcare resources and the future needs.

How to cite this article

Mehta Y, Hegde A, Pande R, Zirpe KG, Gupta V, Ahdal J, et al. Methicillin-resistant Staphylococcus aureus in Intensive Care Unit Setting of India: A Review of Clinical Burden, Patterns of Prevalence, Preventive Measures, and Future Strategies. Indian J Crit Care Med 2020;24(1):55–62.

Effects of the proportion of high-risk patients and control strategies on the prevalence of methicillin-resistant Staphylococcus aureus in an intensive care unit

Background

The presence of nosocomial pathogens in many intensive care units poses a threat to patients and public health worldwide. Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogen endemic in many hospital settings. Patients who are colonized with MRSA may develop an infection that can complicate their prior illness.

Methods

A mathematical model to describe transmission dynamics of MRSA among high-risk and low-risk patients in an intensive care unit (ICU) via hands of health care workers is developed. We aim to explore the effects of the proportion of high-risk patients, the admission proportions of colonized and infected patients, the probability of developing an MRSA infection, and control strategies on MRSA prevalence among patients.

Results

The increasing proportion of colonized and infected patients at admission, along with the higher proportion of high-risk patients in an ICU, may significantly increase MRSA prevalence. In addition, the prevalence becomes higher if patients in the high-risk group are more likely to develop an MRSA infection. Our results also suggest that additional infection prevention and control measures targeting high-risk patients may considerably help reduce MRSA prevalence as compared to those targeting low-risk patients.

Conclusions

The proportion of high-risk patients and the proportion of colonized and infected patients in the high-risk group at admission may play an important role on MRSA prevalence. Control strategies targeting high-risk patients may help reduce MRSA prevalence.

Interprofessional perceptions and emotional impact of multidrug-resistant organisms: A qualitative study

BACKGROUND

Hospital-acquired infections caused by multidrug-resistant organisms (MDROs) are a threat to patient safety and hospital economy. Training in hygiene precautions is known to limit MDRO spread and patient morbidity. As infection prevention is a collaborative task, we developed an interprofessional educational intervention, including a reflective unit about MDRO. This article reports on the perceptions of professionals for MDRO management.

METHODS

In 2017, we conducted 8 trainings, including facilitated group discussions focusing on the question how participants think others experience MDRO. Results were analyzed using a socio-constructivist qualitative approach.

RESULTS

A total of 51 health care workers from 13 professions and 5 hospitals participated, generating 366 items for coding. Three main themes could be identified: (1) significant barriers in educating clinicians and informing lay persons, (2) emotional reactions-especially anxiety and anger-from the perspective of lay persons and professionals evoked by MDRO, and (3) perceived economic burden.

CONCLUSIONS

MDROs generate psychosocial side effects with an impact on health care management and on professional-patient relationships and interprofessional relationships. Specifically, emotions evoked by insufficient information and transparency play a major role. Therefore, hygiene trainings must not be limited to basic skills. In addition, they should be comprised of communication and educational techniques and evoke attentiveness for emotional stress.

Antibiotic susceptibility patterns of Staphylococcus aureus strains isolated at the Yaounde Central Hospital, Cameroon: a retro prospective study

Introduction

Staphylococcus aureus is an important pathogen responsible for hospital and community acquired infection(s). Emerging resistance to methicillin in this organism has left physicians with few therapeutic alternatives to treat infections caused by it. This study was aimed at determining the antibiotic susceptibility patterns of Staphylococcus aureus strains isolated at the Yaounde Central Hospital, Cameroon.

Methods

from January 2014 to November 2016, a total of 250 non repeated strains were isolated from various clinical specimens. Isolates and antibiotic susceptibility profiles were identified through standard microbiological techniques.

Results

methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) accounted respectively for 80% (201/205) and 20% (49/205) of the total strains isolated. MRSA strains displayed high resistance to cefoxitin (100%), cotrimoxazole (89%), vancomycin (79.7%), lincomycin (70.3%), tobramycin (72.5%), doxycycline (68.0%), kanamycin (69.7%) and erythromycin (55.7%). In contrast, a high susceptibility was observed with rifampicin (82.6%). KTG (42.3%) and constitutive MLSB (17.4%) were the most frequent phenotypes recorded.

Conclusion

our results show that the carriage of acquired MRSA infections predominates in this population. Despite the noticeable multiresistance of MRSA strains to antibiotics, rifampicin remains the drugs of choice for the therapy of acquired MRSA infections in this setting. In order to slow down antimicrobial resistance, surveillance studies for antimicrobial susceptibility remains essential to identify resistance and inform policy on resistance.

Characteristics of the antibiotic regimen that affect antimicrobial resistance in urinary pathogens

Background

Treatment duration, treatment interval, formulation and type of antimicrobial (antibiotic) are modifiable factors that will influence antimicrobial selection pressure. Currently, the impact of the route of administration on the occurrence of resistance in humans is unclear.

Methods

In this retrospective multi-center cohort study, we assessed the impact of different variables on antimicrobial resistance (AMR) in pathogens isolated from the urinary tract in older adults. A generalized estimating equations (GEE) model was constructed using 7397 Escherichia coli (E. coli) isolates.

Results

Resistance in E. coli was higher when more antibiotics had been prescribed before isolation of the sample, especially in women (significant interaction p = 0.0016) and up to nine preceding prescriptions it was lower for higher proportions of preceding parenteral prescriptions (significant interactions p = 0.0067). The laboratory identity, dying, and the time between prescription and sampling were important confounders (p < 0.001).

Conclusions

Our model describing shows a dose-response relation between antibiotic use and AMR in E. coli isolated from urine samples of older adults, and, for the first time, that higher proportions of preceding parenteral prescriptions are significantly associated with lower probabilities of AMR, provided that the number of preceding prescriptions is not extremely high (≥10 during the 1.5 year observation period; 93% of 5650 included patients).

Trial registration

Retrospectively registered.

Comparison of viral infection in healthcare-associated pneumonia (HCAP) and community-acquired pneumonia (CAP)

Background

Although viruses are known to be the second most common etiological factor in community-acquired pneumonia (CAP), the respiratory viral profile of the patients with healthcare-associated pneumonia (HCAP) has not yet been elucidated. We investigated the prevalence and the clinical impact of respiratory virus infection in adult patients with HCAP.

Methods

Patients admitted with HCAP or CAP, between January and December 2016, to a tertiary referral hospital in Korea, were prospectively enrolled, and virus identification was performed using reverse-transcription polymerase chain reaction (RT-PCR).

Results

Among 452 enrolled patients (224 with HCAP, 228 with CAP), samples for respiratory viruses were collected from sputum or endotracheal aspirate in 430 (95.1%) patients and from nasopharyngeal specimens in 22 (4.9%) patients. Eighty-seven (19.2%) patients had a viral infection, and the proportion of those with viral infection was significantly lower in the HCAP than in the CAP group (13.8% vs 24.6%, p = 0.004). In both the HCAP and CAP groups, influenza A was the most common respiratory virus, followed by entero-rhinovirus. The seasonal distributions of respiratory viruses were also similar in both groups. In the HCAP group, the viral infection resulted in a similar length of hospital stay and in-hospital mortality as viral–bacterial coinfection and bacterial infection, and the CAP group showed similar results.

Conclusions

The prevalence of viral infection in patients with HCAP was lower than that in patients with CAP, and resulted in a similar prognosis as viral–bacterial coinfection or bacterial infection.

Predictors of colonization with Staphylococcus species among patients scheduled for cardiac and orthopedic interventions at tertiary care hospitals in north-eastern Germany-a prevalence screening study

As methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in humans are a global challenge. In Mecklenburg and Western Pomerania (Germany) 1,517 patients who underwent surgical interventions were systematically screened for MRSA and MSSA colonization on the day of hospital admission and discharge. Demographic data, risk factors and colonization status of the (i) nose, (ii) throat, (iii) groin, and (iv) thorax or site of surgical intervention were determined. Of the 1,433 patients who were included for further evaluation, 331 (23.1%) were colonized with MSSA, while only 17 (1.2%) were MRSA carriers on the day of hospital admission. A combination of nose, throat and groin swabs returned a detection rate of 98.3% for MSSA/MRSA. Trauma patients had lower prevalence of MRSA/MSSA (OR 0.524, 95% CI: 0.37-0.75; p < 0.001) than patients with intended orthopedic interventions. Males showed significantly higher nasal S. aureus carrier rates than females (odds ratio (OR) = 1.478; 95% CI: 1.14-1.92; p = 0.003). Nasal S. aureus colonization was less frequent among male smokers as compared to non-smokers (chi² = 16.801; phi = 0.154; p < 0.001). Age, gender and smoking had a significant influence on S. aureus colonization. Combining at least three different swabbing sites should be considered for standard screening procedure to determine S. aureus colonization at patients scheduled for cardiac or orthopedic interventions at tertiary care hospitals.

Hospital-associated methicillin-resistant Staphylococcus aureus: A cross-sectional analysis of risk factors in South African tertiary public hospitals

Introduction

Hospital-associated methicillin-resistant S. aureus (HA-MRSA) remains a significant cause of morbidity and mortality worldwide. We conducted a study to determine risk factors for HA-MRSA in order to inform control strategies in South Africa.

Methods

We used surveillance data collected from five tertiary hospitals in Gauteng and Western Cape provinces during 2014 for analysis. A case of HA-MRSA was defined as isolation of MRSA from a blood culture 48 hours after admission and/or if the patient was hospitalised in the six months prior to the current culture. Multivariable logistic regression modelling was used to determine risk factors for HA-MRSA.

Results

Of the 9971 patients with positive blood cultures, 7.7% (772) had S. aureus bacteraemia (SAB). The overall prevalence of MRSA among those with SAB was 30.9% (231/747; 95% confidence interval [CI] 27.6%– 34.3%). HA-MRSA infections accounted for 28.3% of patients with SAB (207/731; 95% CI 25.1%– 31.7%). Burns (adjusted odds ratio [aOR] 12.7; 95% CI 4.7–34.4), age ≤1 month (aOR 8.7; 95% CI 3.0–24.6), residency at a long-term care facility (aOR 5.2; 95% CI, 1.5–17.4), antibiotic use within two months of the current SAB episode (aOR 5.1; 95% CI 2.8–9.1), hospital stay of 13 days or more (aOR 2.8; 95% CI 1.3–5.6) and mechanical ventilation (aOR 2.2; 95% CI 1.07–4.6), were independent risk factors for HA-MRSA infection.

Conclusion

The prevalence of MRSA remains high in South African tertiary public hospitals. Several identified risk factors of HA-MRSA infections should be considered when instituting infection and prevention strategies in public-sector hospitals, including intensifying the implementation of antimicrobial stewardship programmes. There is an urgent need to strengthen infection prevention and control in burn wards, neonatal wards, and intensive care units which house mechanically ventilated patients.

Inducible clindamycin and methicillin resistant Staphylococcus aureus in a tertiary care hospital, Kathmandu, Nepal

Background

Staphylococcus aureus, an important nosocomial pathogen, is frequently associated with infections in human. The management of the infections by it especially methicillin resistant ones is often difficult because methicillin resistant S. aureus is usually resistant to multiple antibiotics. Macrolide-lincosamide streptogramin B family of antibiotics is commonly used to treat such infections as an alternative to vancomycin.

Methods

This study was conducted over the period of one and half year from November 2013–April 2015 in Microbiology laboratory of Nepal Medical College and Teaching Hospital, Kathmandu, Nepal to find the incidence of different phenotypes of MLS_B resistance among S. aureus from clinical samples and their association with methicillin resistance. Two hundred seventy isolates of S. aureus were included in the study. Methicillin resistance was detected by cefoxitin disc diffusion method and inducible clindamycin resistance by erythromycin and clindamycin disc approximation test (D-test).

Results

Of the 270 clinical isolates of S. aureus, 25.1% (68/270) were MRSA. Erythromycin and clindamycin resistance was seen in 54.4% (147/270) and 41.8% (113/270) isolates respectively. Resistance to erythromycin and clindamycin were higher in MRSA as compared to MSSA (erythromycin-resistance: 88.2% Vs 39.1% and clindamycin-resistance: 79.4% Vs 41.8%). The overall prevalence of _iMLS_B and _cMLS_B phenotype was 11.48% (31/270) and 29.25% (79/270) respectively. Both _iMLS_B and _cMLS_B phenotypes predominated in MRSA strains.

Conclusions

Detection rate of MRSA in our study shows the necessity to improve in healthcare practices and to formulate new policy for the control of MRSA infections. Clindamycin resistance in the form of _iMLS_B and _cMLS_B especially among MRSA emphasizes the need of D-test to be performed routinely in our set up while using clindamycin as an alternative choice to anti-staphylococcal antibiotics like vancomycin and linezolid in the treatment of staphylococcal infections.

Characterization of Staphylococcus aureus infections in children with Down syndrome

Staphylococcus aureus infections in the Down syndrome (DS) population have not been well characterized. This study determined clinical and molecular characteristics of S. aureus infections in children with DS followed at Texas Children's Hospital (TCH), from 2001 to 2011. Patients were retrospectively identified from an ongoing S. aureus surveillance study. Medical records were reviewed. Isolates were characterized by antimicrobial susceptibility, pulsed-field gel electrophoresis patterns, and detection of PVL genes (pvl), mupA (high-level mupirocin resistance gene), smr (chlorhexidine resistance conferring gene), and Staphylococcal Chromosomal Cassette mec (SCCmec) type. Twenty-six patients with DS had a total of 34 S. aureus infections (8 recurrent); 61% were MRSA. DS patients represented 16.8 per 10,000 community onset S. aureus infections seen at TCH. Among 26 initial infections 17 were skin and soft tissue (SSTI), 7 were outer or middle ear and 2 were invasive infections. Seventeen patients were hospitalized. Thirteen (65%) of 20 available isolates were USA300, 14 were pvl+, 5 were mupA+, and 8 were smr+. Five of 8 (63%) recurrent infections were ear infections. All 4 recurrent ear isolates available for study were smr+, ciprofloxacin non-susceptible and treated with ciprofloxacin otic drops. S. aureus infections among patients with DS were similar in presentation to other patient groups, except for a greater proportion being associated with ear infections. Seventy percent of ear fluid isolates carried antiseptic and fluoroquinolone resistance genes. A study of a greater number of DS patients is warranted to further explore these findings.

Antibiotic Exposure and Other Risk Factors for Antimicrobial Resistance in Nasal Commensal Staphylococcus aureus: An Ecological Study in 8 European Countries

Objectives

Antimicrobial resistance (AMR) has become a global public health concern which threatens the effective treatment of bacterial infections. Resistant Staphylococcus aureus (including MRSA) increasingly appears in individuals with no healthcare associated risks. Our study assessed risk factors for nasal carriage of resistant S. aureus in a multinational, healthy, community-based population, including ecological exposure to antibiotics.

Methods

Data were collected in eight European countries (Austria, Belgium, Croatia, France, Hungary, the Netherlands, Spain and Sweden). Commensal AMR patterns were assessed by collecting 28,929 nasal swabs from healthy persons (aged 4+). Ecological exposure to antibiotics was operationalized as systemic antibiotic treatment patterns, extracted from electronic medical records of primary care practices in which the participants were listed (10–27 per country). A multilevel analysis related AMR in nasal commensal S. aureus to antibiotic exposure and other risk factors (e.g. age and profession).

Results

Of the 6,093 S. aureus isolates, 77% showed resistance to at least one antibiotic. 7.1% exhibited multidrug resistance (defined as resistance to 3 or more antibiotic classes), and we found 78 cases MRSA (1.3%). A large variation in antibiotic exposure was found between and within countries. Younger age and a higher proportion of penicillin prescriptions in a practice were associated with higher odds for carriage of a resistant S. aureus. Also, we found higher multidrug resistance rates in participants working in healthcare or nurseries.

Conclusions

This study indicates that in a population with no recent antibiotic use, the prescription behavior of the general practitioner affects the odds for carriage of a resistant S. aureus, highlighting the need for cautious prescribing in primary care. Finally, since variation in AMR could partly be explained on a national level, policy initiatives to decrease AMR should be encouraged at the national level within Europe.

Environmental monitoring of bacterial contamination and antibiotic resistance patterns of the fecal coliforms isolated from Cauvery River, a major drinking water source in Karnataka, India

The present study focuses prudent elucidation of microbial pollution and antibiotic sensitivity profiling of the fecal coliforms isolated from River Cauvery, a major drinking water source in Karnataka, India. Water samples were collected from ten hotspots during the year 2011-2012. The physiochemical characteristics and microbial count of water samples collected from most of the hotspots exhibited greater biological oxygen demand and bacterial count especially coliforms in comparison with control samples (p ≤ 0.01). The antibiotic sensitivity testing was performed using 48 antibiotics against the bacterial isolates by disk-diffusion assay. The current study showed that out of 848 bacterial isolates, 93.51% (n = 793) of the isolates were found to be multidrug-resistant to most of the current generation antibiotics. Among the major isolates, 96.46% (n = 273) of the isolates were found to be multidrug-resistant to 30 antibiotics and they were identified to be Escherichia coli by 16S rDNA gene sequencing. Similarly, 93.85% (n = 107), 94.49% (n = 103), and 90.22% (n = 157) of the isolates exhibited multiple drug resistance to 32, 40, and 37 antibiotics, and they were identified to be Enterobacter cloacae, Pseudomonas trivialis, and Shigella sonnei, respectively. The molecular studies suggested the prevalence of bla TEM genes in all the four isolates and dhfr gene in Escherichia coli and Sh. sonnei. Analogously, most of the other Gram-negative bacteria were found to be multidrug-resistant and the Gram-positive bacteria, Staphylococcus spp. isolated from the water samples were found to be methicillin and vancomycin-resistant Staphylococcus aureus. This is probably the first study elucidating the bacterial pollution and antibiotic sensitivity profiling of fecal coliforms isolated from River Cauvery, Karnataka, India.

Colonisation with ESBL-producing and carbapenemase-producing Enterobacteriaceae, vancomycin-resistant enterococci, and meticillin-resistant Staphylococcus aureus in a long-term care facility over one year

Background

This study examined colonisation with and characteristics of antimicrobial-resistant organisms among residents of a long-term care facility (LTCF) over one year, including strain persistence and molecular diversity among isolates of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae.

Methods

Sixty-four residents of a LTCF were recruited (51 at baseline, 13 during the year). Data on dependency levels, hospitalisations, and antimicrobial prescribing were collected. Nasal and rectal swabs and catheter urine specimens were examined quarterly, using chromogenic agars, for ESBL-producing Enterobacteriaceae, carbapenemase-producing Enterobacteriaceae (CPE), vancomycin-resistant enterococci (VRE), and meticillin-resistant S. aureus (MRSA). All ESBL-producing E. coli (ESBL-EC) were characterised by pulsed-field gel electrophoresis (PFGE) and PCR to assess for sequence type (ST) ST131, its resistance-associated H30 and H30-Rx subclones, and bla_CTX-M,bla_TEM,bla_SHV, and bla_OXA-1.

Results

The overall number of residents colonised, by organism, was as follows: ESBL-EC, 35 (55%); MRSA, 17 (27%); ESBL-producing K. pneumoniae (ESBL-KP), 5 (8%); VRE, 2 (3%) and CPE, 0 (0%). All 98 ESBL-EC isolates were H30-Rx ST131, with bla_{CTX-M-group 1.} By PFGE, a group of 91 ESBL-EC (from 33 participants) had ≥ 85% similar profiles and resembled UK epidemic strain A/ international pulsotype PFGE812. Sequential ESBL-EC from individual residents were closely related. Six ESBL-KP isolates, from five participants, had bla_{CTX-M-group 1} and by PFGE were closely related. Colonisation with ESBL and MRSA was associated with location within the LTCF and previous exposure to antimicrobials.

Conclusions

Among LTCF residents, colonisation with ESBL-EC and MRSA was common. All ESBL-EC were H30-Rx ST131, consistent with clonal dissemination.

Applying Convergent Immunity to Innovative Vaccines Targeting Staphylococcus aureus

Recent perspectives forecast a new paradigm for future “third generation” vaccines based on commonalities found in diverse pathogens or convergent immune defenses to such pathogens. For Staphylococcus aureus, recurring infections and a limited success of vaccines containing S. aureus antigens imply that native antigens induce immune responses insufficient for optimal efficacy. These perspectives exemplify the need to apply novel vaccine strategies to high-priority pathogens. One such approach can be termed convergent immunity, where antigens from non-target organisms that contain epitope homologs found in the target organism are applied in vaccines. This approach aims to evoke atypical immune defenses via synergistic processes that (1) afford protective efficacy; (2) target an epitope from one organism that contributes to protective immunity against another; (3) cross-protect against multiple pathogens occupying a common anatomic or immunological niche; and/or (4) overcome immune subversion or avoidance strategies of target pathogens. Thus, convergent immunity has a potential to promote protective efficacy not usually elicited by native antigens from a target pathogen. Variations of this concept have been mainstays in the history of viral and bacterial vaccine development. A more far-reaching example is the pre-clinical evidence that specific fungal antigens can induce cross-kingdom protection against bacterial pathogens. This trans-kingdom protection has been demonstrated in pre-clinical studies of the recombinant Candida albicans agglutinin-like sequence 3 protein (rAls3) where it was shown that a vaccine containing rAls3 provides homologous protection against C. albicans, heterologous protection against several other Candida species, and convergent protection against several strains of S. aureus. Convergent immunity reflects an intriguing new approach to designing and developing vaccine antigens and is considered here in the context of vaccines to target S. aureus.

High prevalence of methicillin resistant staphylococci strains isolated from surgical site infections in Kinshasa

INTRODUCTION

Surgical site infections (SSIs) after surgery are usually caused by Staphylococcus aureus and coagulase-negative staphylococci (CNS). In low income countries, methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase-negative staphylococci (MR-CNS) surgical site infections are particularly associated with high treatment cost and remain a source of mortality and morbidity. This study aimed to determine the prevalence and the sensitivity to antibiotics of MRSA and MR-CNS isolated from SSIs.

METHODS

Wound swabs were collected from 130 hospitalized surgical patients in two major hospitals of Kinshasa. S. aureus and CNS strains were identified by standard microbiological methods and latex agglutination test (Pastorex Staph-Plus). The antibiotic susceptibility of all staphylococcal strains was carried out using disk-diffusion method.

RESULTS

Eighty nine staphylococcal strains were isolated. Out of 74 S. aureus and 15 CNS isolated, 47 (63.5%) and 9 (60%) were identified as MRSA and MR-CNS respectively. Among the MRSA strains, 47 strains (100%) were sensitive to imipenem, 39 strains (89%) to amoxycillin-clavulanic acid and 38 strains (81%) to vancomycin. All MR-CNS were sensitive to imipenem, amoxycillin-clavulanic acid and vancomycin. The isolated MRSA and MR-CNS strains showed multidrug resistance. They were both resistant to ampicillin, cotrimoxazole, erythromycin, clindamycin, ciprofloxacin, cefotaxime and ceftazidime.

CONCLUSION

The results of the present study showed a high prevalence of MRSA and MR-CNS. Imipenem, amoxycillin-clavulanic acid and vancomycin were the most active antibiotics. This study suggests that antibiotic surveillance policy should become national priority as MRSA and MR-CNS were found to be multidrug resistant.