Prevalence Of Staphylococcus Aureus Research Articles

#68 Prevalence of Staphylococcus aureus bacteremia at Saint Damien Hospital, Nos Petits Frères et Sœurs January 2020-June 2021, Haiti

Abstract Background Nosocomial bacteremia is a healthcare-associated infection. It presents significant morbidity and mortality. Its prevention is based on the control of the risk factors, collection, and analysis of data to set up actions and measures aimed at educating staff, patients, and families to mitigate complications. Bacteremia is regularly monitored at Saint Damien Hospital (HSD);an increase in Staphylococcus aureus (SA) bacteremia was observed in January 2020. All SA infections were reviewed at St Damien during eighteen months to determine the prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-sensitive Staphylococcus aureus (MSSA) and the distribution by unit. Also, the frequency of nosocomial and community SA was determined. Nosocomial infections and those associated with SA remain a public health concern because of the antimicrobial resistance, the death rate, and the associated cost. Method A descriptive retrospective study was carried out over a period from January 2020 to June 2021 for all patients hospitalized in pediatrics who underwent a blood culture and whose results reported SA. Data were collected from microbiology laboratory registers and patient records. Results From January 2020 to June 2021, two thousand two hundred thirty-five (n = 2235) blood cultures were performed for a total of four thousand two hundred eighty-seven (n=4287) admissions. From these blood cultures performed, 11% of microorganisms (n=479) were isolated, of which 18.37% are SA (n=88). From these SA 68% were resistant to methicillin/MRSA (n=60), 32% sensitive to methicillin/MSSA (n=28).51% (n= 45) were associated with nosocomial infections (NI), 49% (n= 43) related to community infections. From the MRSA strains, 57% (n=34) are of nosocomial (NI) and 43% (n=26) are of community infection. These strains mainly came from emergency services 40% (n=24) followed by neonatology 22% (13) and intensive care 17% (10 ). The mortality rate for MRSA and MSSA were 32% (n=19) and 18% (n=5), respectively. 40% of MRSA isolates were multi-drug resistant (n=24). The resistance rate was 76% for penicillin (n=67) 65% for oxacillin (n=57) 35% for cefoxitin (n=31). Conclusion The frequency of isolation of Staphylococcus Aureus (SA) as well as the prevalence of SA and MRSA infections, was relatively high during this period. Its existence in a community setting and multidrug resistance to antibiotics is an alert making this bacteremia a public health priority to be monitored and brought under control.

Antibiotic resistance is lower in Staphylococcus aureus isolated from antibiotic-free raw meat as compared to conventional raw meat.

The frequent use of antibiotics contributes to antibiotic resistance in bacteria, resulting in an increase in infections that are difficult to treat. Livestock are commonly administered antibiotics in their feed, but there is current interest in raising animals that are only administered antibiotics during active infections. Staphylococcus aureus (SA) is a common pathogen of both humans and livestock raised for human consumption. SA has achieved high levels of antibiotic resistance, but the origins and locations of resistance selection are poorly understood. We determined the prevalence of SA and MRSA in conventional and antibiotic-free (AF) meat products, and also measured rates of antibiotic resistance in these isolates. We isolated SA from raw conventional turkey, chicken, beef, and pork samples and also from AF chicken and turkey samples. We found that SA contamination was common, with an overall prevalence of 22.6% (range of 2.8–30.8%) in conventional meats and 13.0% (range of 12.5–13.2%) in AF poultry meats. MRSA was isolated from 15.7% of conventional raw meats (range of 2.8–20.4%) but not from AF-free meats. The degree of antibiotic resistance in conventional poultry products was significantly higher vs AF poultry products for a number of different antibiotics, and while multi-drug resistant strains were relatively common in conventional meats none were detected in AF meats. The use of antibiotics in livestock contributes to high levels of antibiotic resistance in SA found in meat products. Our results support the use of AF conditions for livestock in order to prevent antibiotic resistance development in SA.

1215. Geographic Distribution of Staphylococcus aureus With Reduced Sensitivity and Resistance to Vancomycin in the Dominican Republic

BackgroundResistant Staphylococcus aureus (SA) poses a major challenge to clinicians. The prevalence of methicillin-resistant SA (MRSA) has increased over the past decades, while vancomycin resistance remains rare. Only 14 cases of vancomycin-resistant SA (VRSA) have been described in the United States since 2002. VRSA and SA with reduced susceptibility to vancomycin (VISA) cause high morbidity and mortality. There is a paucity of data on VRSA in developing nations. We seek to define the prevalence and resistance profile of SA in the Dominican Republic (DR).MethodsThis is a retrospective review of resistance patterns of SA isolates from a clinical laboratory in the DR (Amadita Laboratories). Amadita provides services nationwide. Data collected from 2016 to 2017 included SA phenotypic sensitivity patterns and geographic location and income level. VISA and VRSA were defined as having minimum inhibitory (MIC) concentrations between 4 and 8 and MIC >16.ResultsOf 5,372 SA samples, 2,735 (51%) were MRSA, 21 were VISA and 39 were VRSA. VRSA samples were more commonly from Santo Domingo (SD) (Figure 1). Communities in SD with mixed and low incomes had greater burden of VRSA (Figure 2). Antimicrobial susceptibilities are shown in Table 1.Figure 1.VRSA samples in the DR by location.Figure 2.VRSA samples in Metropolitan SD based on income level of communities.Table 1: Antimicrobial Susceptibility for SA Isolates by Drug Resistance Category (%)CiprofloxacinClindamycinErythromycinGentamicinLevofloxacinLinezolidOxacillinQuinupristin-DalfopristinPenicillin GTrimethoprim Sulfamethoxazole (TMP-SMX)RifampinTetracyclinesTigecyclineVISA812333908010052100010010057100VRSA874351948794641006929771100ConclusionIn this nationwide sample, we found an alarming number of VISA and VRSA. Most cases were in metropolitan SD, with lower income communities carrying a higher case burden. Linezolid and TMP-SMX retain activity against VISA and VRSA in the DR. The rise of vancomycin resistance in developing countries and the disproportionate burden on communities of low income is concerning and requires further study. Infection control measures and antimicrobial stewardship interventions may help prevent further spread of resistant strains.Disclosures All authors: No reported disclosures.

Pediatric neck abscesses: No increase in methicillin-resistant Staphylococcus aureus

IntroductionRecent studies from Western countries showed an increased incidence rate of methicillin-resistant Staphylococcus aureus (MRSA) isolated from pediatric neck abscesses cultures. We sought to examine the microbiology and antibiotic susceptibility of such samples over a 10-year period, and particularly of Staphylococcus aureus (SA), in order to determine whether a similar trend exists in our institution. MethodsA retrospective chart review of children ≤18 years that underwent needle aspiration or surgical drainage of neck abscesses, including suppurative lymphadenitis, retropharyngeal abscesses, and parapharyngeal abscesses was conducted between 1/1/06–31/12/15. ResultsSixty-two children were identified with a male predominance (34, 55%). The median age was 2 years. There were 37 (60%) suppurative lymphadenitis, 15 (24%) parapharyngeal abscess, and 10 (16%) retropharyngeal abscess cases. Twenty-nine (47%) children received antibiotic treatment prior to admission, most commonly β-lactam agents. Of them, 15 (52%) had positive cultures, including 7 (47%) with SA. On admission, 45 (73%) children had already received amoxicillin-clavulanate. Of those who did not improve, 16 (26%) received ceftriaxone and clindamycin. Twenty-one (38%) cultures were negative. The most common isolated bacteria were SA in 13 (24%), Streptococcus pyogenes in 7 (13%), and Streptococcus viridians group in 9 (16%). Of the SA isolates, there was only 1 (8%) case of MRSA; however, there were 4 (31%) clindamycin-resistant SA isolates. ConclusionUnlike previously published data, there was no increase in MRSA incidence at our institution. However, the high prevalence of clindamycin-resistant SA was in line with previous reports. These findings should be considered when starting empirical therapy in pediatric neck abscesses.

Longevity and gender as the risk factors of methicillin-resistant Staphylococcus aureus infections in southern Poland

BackgroundThe proportion of older people among the general population has risen. Staphylococcus aureus (SA) constitutes a significant problem. Underlying disease and functional debility, predispose the older adult to staphylococcal carriage and infection, specially bloodstream infection and pneumonia.MethodsThis is a retrospective cohort study of older patients with SA infections. We analyzed a database containing the results of laboratory cultures from patients treated in 2013 for SA infections and selected 613 hospitalized and non-hospitalized people aged ≥60 years.ResultsThe prevalence of Methicillin-resistant SA (MRSA) were significantly different in categories of patients: from 14.1% in young old, 19.5% in old old and 26.7 in longevity. MRSA was significantly more frequently reported in cases of pneumonia, 40.4% of SA strains (p < 0.0001, OR 0.3, 95%CI 0.14–0.49). The nosocomial MRSA infections were more common in ICU departments: prevalence 36.8%, than in non-ICU departments: prevalence 17.3% (OR 2.8, 95%CI 1.06–7.34, p = 0.014). Bloodstream infections, which accounted for 6% of all infections, were more frequent in males (p = 0.0231, OR 2.25, 95%CI 1.098–4.604). The greatest increase in antibiotic resistance was related to trimethoprim/sulfamethoxazole (TMP/SXT), which increased to over 80% in the older study groups. All age groups demonstrated increased MIC90 values for glycopeptide and tigecycline. Although strains isolated from patients in all age groups remained sensitive to vancomycin, strains isolated from patients in the old-old and longevity groups demonstrated resistance to teicoplanin. The MIC90 for tigecycline was the highest in the group aged >90 years.ConclusionsMRSA constitutes a significant epidemiological problem in cases of hospital-treated pneumonia. The findings were similar for long-term-care facilities, where MRSA appears to affect male residents in particular, although there were fewer male residents than female residents. The low sensitivity to TMP/SXT of SA strains isolated from the oldest patients indicates potentially serious challenges pertaining to efficacious treatment of SA infections.

Prevalence and correlates of MRSA and MSSA nasal carriage at a Ugandan regional referral hospital.

Despite increasing antimicrobial resistance globally, data are lacking on prevalence and factors associated with Staphylococcus aureus (SA) and MRSA carriage in resource-limited settings. To determine the prevalence of SA and MRSA nasal carriage and factors associated with carriage among Ugandan regional referral hospital patients. We enrolled a cross-section of 500 adults, sampling anterior nares for SA and MRSA carriage using Cepheid Xpert SA Nasal Complete. Mean age was 37 years; 321 (64%) were female and 166 (33%) were HIV infected. Overall, 316 (63%) reported risk factors for invasive SA infection; 368 (74%) reported current antibiotic use. SA was detected in 29% and MRSA in 2.8%. MRSA and MSSA carriers were less likely than SA non-carriers to be female (50% and 56% versus 68%, P = 0.03) or to have recently used β-lactam antibiotics (43% and 65% versus 73%, P = 0.01). MRSA carriers were more likely to have open wounds than MSSA carriers and SA non-carriers (71% versus 27% and 40%, P = 0.001) and contact with pigs (21% versus 2% and 6%, P = 0.008). MRSA carriage ranged from 0% of HIV clinic participants to 8% of inpatient surgical ward participants ( P = 0.01). In multivariable logistic regression analysis, male sex was independently associated with SA carriage (OR 1.68, 95% CI 1.12-2.53, P = 0.01) and recent β-lactam antibiotic use was associated with reduced odds of SA carriage (OR 0.61, 95% CI 0.38-0.97, P = 0.04). MRSA nasal carriage prevalence was low and associated with pig contact, open wounds and surgical ward admission, but not with HIV infection.

Staphylococcus aureus, Including Meticillin-Resistant Staphylococcus aureus, among General Practitioners and Their Patients: A Cross-Sectional Study.

BackgroundThe role of general practitioners (GPs) as reservoir and potential source for Staphylococcus aureus (SA) transmission is unknown. Our primary objective was to evaluate the prevalence of SA and community-acquired methicillin resistant SA (CA-MRSA) carrier status (including spa typing) among GPs and their patients in Belgium. The secondary objective was to determine the association between SA/CA-MRSA carriage in patients and their characteristics, SA carriage in GPs, GP and practice characteristics.MethodsThe Belgian GPs, who swabbed their patients in the APRES study (which assessed the prevalence of SA nasal carriage in nine European countries; November 2010 –June 2011), were asked to swab themselves as well (May-June 2011). GPs and their patients had to complete a questionnaire on factors related to SA carriage and transmission. SA isolation including CA-MRSA and spa typing was performed on the swabs.ResultsIn eighteen practices 34 GPs swabbed patients of which 25 GPs provided personal swabs. The analysis was performed on 3008 patient records. Among GPs SA carriage (28%) was more prevalent than among their patients (19.2%), but CA-MRSA carriage was not present. SA was more prevalent among younger patients and those living with cattle. Spa typing SA and MRSA strains did not suggest correlation within practices or between patients and GPs, but chronic skin conditions of GPs and always handshaking patients by SA positive GPs were associated with more SA among patients, and hand washing after every patient contact with less SA among patients in practices with high antibiotic prescribing rates.ConclusionNo MRSA was found among GPs, although their SA carriership was higher compared to their patients’. Spa types did not cluster within practices, possibly due to difference in timing of swabbing. To minimise SA transmission to their patients GPs should consider taking appropriate care of their chronic skin diseases, antibiotic prescribing behaviour, handshaking and hand washing habits.

Reappearance and treatment of penicillin-susceptible Staphylococcus aureus in a tertiary medical centre.

The purpose of this study was to describe trends in the prevalence and treatment patterns of penicillin-susceptible Staphylococcus aureus (SA) infections. This was a cross-sectional study of MSSA isolates from blood cultures at a tertiary-care centre between 1 January 2003 and 31 December 2012. All blood cultures positive for MSSA drawn during the study period were used to calculate the prevalence of penicillin-susceptible SA. Repeat cultures were excluded if they were isolated within 6 weeks of the index culture. The analysis was then restricted to inpatient blood cultures to assess treatment patterns. Antibiotics administered 48-96 h after the culture were analysed. A total of 446 blood cultures positive for MSSA were included in the analysis. There was a distinct trend showing an increase in the percentage of penicillin-susceptible SA over 10 years from 13.2% (95% CI 4.1%-22.3%) in 2003 to 32.4% (95% CI 17.3%-47.5%) in 2012 (P trend <0.001). During the study period, penicillin use for penicillin-susceptible SA bacteraemia increased from 0.0% in 2003-04 to 50.0% in 2011-12 (P trend = 0.007). Over a decade, there was an ∼3-fold increase in penicillin susceptibility among MSSA blood cultures at a large tertiary-care facility. Although treatment with penicillin increased over the study period, only 50% of penicillin-susceptible SA was treated with penicillin in the final study period. This study suggests that while susceptibility to penicillin appears to be returning in SA, the use of penicillin for penicillin-susceptible SA bacteraemia is low.

Efficacy of Pre-Operative Nasal Staphylococcus aureus Screening and Chlorhexidine Chest Scrub in Decreasing the Incidence of Post-Resection Empyema

We evaluated the efficacy of pre-operative Staphylococcus aureus (SA) screening and chlorhexidine chest scrub in decreasing the incidence of empyema after major pulmonary resections. For two years, a strategy aimed at decreasing post-resection empyema was instituted. This entailed pre-operative screening for nasal SA and chlorhexidine chest scrub the night before surgery (Group Swab-Scrub, n=192). Patients screened positive for SA, methicillin-resistant (MRSA) and methicillin-sensitive (MSSA), received 5 d of nasal mupirocin. Group Swab-Scrub was compared with patients two years earlier, who did not receive this pre-operative maneuver (Group Control, n=173). The extent of resection considered was lobectomy or greater. All patients received cefazolin (or clindamycin if allergic) prior to incision and 24 h postoperatively, except for patient in Group Swab-Scrub screening positive for MRSA, who received vancomycin. All patients had povidone-iodine skin preparation. In Group Swab-Scrub, prevalence of nasal SA was 8.9% (17/192) two with MRSA and 15 with MSSA. There was no difference in patient demographics or operative characteristics between the Group Swab-Scrub and Group Control. There was also no difference in prolonged air-leak, empyema, wound infection, pneumonia, or mortality rates between the two groups. When stratifying for the extent of procedure, there was no difference in the incidence of empyema after lobectomy (Group Swab-Scrub, 3.9% [7/177] versus Group Control, 2.0% [3/151]; p=0.352) or pneumonectomy (Group Swab-Scrub, 6.7% [1/15] versus Group Control, 13.6% [3/22]; p=0.633). In both univariate and multivariable analysis, prolonged air-leak and pneumonectomy were significant risk factors for empyema. Preoperative screening for nasal SA and chlorhexidine chest scrub does not seem to decrease empyema rates after major pulmonary resection. Prolonged air-leak and pneumonectomy continue to be significant risk factors for developing empyema. The number of patients undergoing pneumonectomy in this study is small and further studies are needed for this patient population.

Prevalence and characterization of Staphylococcus aureus and Staphylococcus pseudintermedius isolated from companion animals and environment in the veterinary teaching hospital in Zambia, Africa

The Republic of Zambia consists of only one veterinary teaching school at the University of Zambia (UNZA) where students and veterinarians are exposed to many bacterial pathogens including Staphylococcus aureus (SA) and Staphylococcus pseudintermedius (SP). The aim of this study was the characterization and antimicrobial susceptibility profile of eleven SA and 48 SP isolates from the veterinary hospitals' in- and outpatients and the environment. No isolate was resistant to cefoxitin by disk diffusion test and the corresponding resistance gene mecA was not found. In contrast, the resistance rates of SA to penicillin (63.6%) and trimethoprim-sulfamethoxazole (36.4%) and SP to penicillin (52.1%) and tetracycline (25.0%) were the highest. A variety of sequence types (STs) without a predominant type including numerous novel types were determined, especially for SP (39.6%). The spa typing provided a clonal assignment for all SAs (100%) and 24 SPs (50%) with three and two novel types, respectively. This study has provided an overview of SA and SP in the veterinary teaching hospital at UNZA. However, for a better understanding of these species regarding pathogenesis and transmission, further studies on the prevalence and characterization of SA and SP from veterinary staff, pet owners, and farm animals in Zambia is needed.

Clinical consequences of using PNA-FISH in Staphylococcal bacteraemia

To optimize patient treatment and rational use of antimicrobials, it is important to provide fast information on findings in blood-cultures (BCs). The purpose of this study was to evaluate the impact of using peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) on positive BCs containing Gram-positive cocci in clusters to differentiate between Staphylococcus aureus (SA) and coagulase negative staphylococci (CoNS) on the prescribed antimicrobial therapy and on the number of contacts between microbiologist and clinician. All cases of positive BCs in our laboratory with SA or CoNS in the year 2011 were identified and the charts were reviewed retrospectively. The group of patients with BCs tested with PNA-FISH was compared to the group of patients with untested BCs. A total of 200 patients with SA and 725 patients with CoNS were included. The mean number of contacts was 0.82 when PNA-FISH showed CoNS and 1.39 when PNA-FISH was not done (p < 0.0001). More patients were recommended appropriate antimicrobial therapy for SA bacteraemia in the PNA-FISH group (98.0%) than in the non-PNA-FISH group (89.4 %) (p = 0.025). The percentage treated with dicloxacillin was 29.6 in the PNA-FISH group, and 8.2 in the non-PNA-FISH group (p = 0.0003). The use of PNA-FISH on BCs in this study was associated with more appropriate and narrow spectrum antimicrobial therapy for patients with SA in an area with low prevalence of methicillin-resistant SA, and a lower number of contacts between clinical microbiologist and clinician about BCs with CoNS as contaminants.

Prevalence and abundance of Staphylococcus aureus in the middle meatus of patients with chronic rhinosinusitis, nasal polyps, and asthma

Chronic rhinosinusitis (CRS) is an idiosyncratic and multifactorial disease process. Bacteria play a role in some patients, by infection or stimulation of inflammation. Staphylococcus aureus (SA) appears to be implicated in a number of infectious and inflammatory mechanisms, and may be particularly relevant in CRS patients with nasal polyps and asthma. Middle meatus swabs from control and CRS patients collected during endoscopic sinus surgery were analyzed by quantitative polymerase chain reaction (QPCR). Total bacterial count, SA prevalence, and SA abundance were examined with respect to patient demographics and disease characteristics. Total bacteria, as measured by QPCR, was not statistically different between controls, CRS without nasal polyps (CRSsNP), CRS with nasal polyps (CRSwNP), or CRS with asthma groups (p < 0.09). Total bacterial counts did not correlate with disease severity as measured by Lund-Mackay computed tomography (CT) scores (p = 0.65). The prevalence of SA was similar between groups (15-25%); however, the abundance increased in CRS patients with allergic rhinitis, nasal polyps, and asthma. The paranasal sinuses are not sterile. SA is implicated in a subset of CRS patients with nasal polyps and/or asthma. Further study is required to predict this subset of patients, and to define the mechanisms of SA pathogenesis.

Resistance to penicillin of Staphylococcus aureus isolates from cows with high somatic cell counts in organic and conventional dairy herds in Denmark

BackgroundQuarter milk samples from cows with high risk of intramammary infection were examined to determine the prevalence of Staphylococcus aureus (SA) and penicillin resistant SA (SAr) in conventional and organic dairy herds and herds converting to organic farming in a combined longitudinal and cross-sectional study.Methods20 conventional herds, 18 organic herds that converted before 1995, and 19 herds converting to organic farming in 1999 or 2000 were included in the study. Herds converting to organic farming were sampled three times one year apart; the other herds were sampled once. Risk of infection was estimated based on somatic cell count, milk production, breed, age and lactation stage.ResultsThe high-risk cows represented about 49 % of the cows in the herds. The overall prevalence of SA and SAr among these cows was 29% (95% confidence interval: 24%–34%) and 4% (95% confidence interval: 2%–5%) respectively. The prevalence of penicillin resistance among SA infected cows was 12% (95% confidence interval: 6%–19%) when calculated from the first herd visits. No statistically significant differences were observed in the prevalence of SAr or the proportion of isolates resistant to penicillin between herd groups.ConclusionThe proportion of isolates resistant to penicillin was low compared to studies in other countries except Norway and Sweden. Based on the low prevalence of penicillin resistance of SA, penicillin should still be the first choice of antimicrobial agent for treatment of bovine intramammary infection in Denmark.

A Cluster of Staphylococcus aureus in Pediatric Cardiac Surgery Leads to Identification of Prevalence of SA Colonization in the Cardiac Surgery Team

ISSUE: A cluster of four Staphylococcus aureus (SA) pediatric cardiac surgical site infections (SSIs) was noted within a 2-week period. We evaluated whether staff working in cardiac surgery were colonized with SA and could have transmitted SA to patients. PROJECT: The hands and nares of all staff involved in cardiac surgery (CS) were cultured using standard techniques. This included cardiology staff entering the operating room. In total, 78 staff and 27 environmental cultures were (EC) done. EC included machinery taken into the operating room (OR) and surfaces in two of four ORs. All isolates from both patients and staff were typed using pulsed-field gel electrophoresis (PFGE) to determine if a clonal relationship existed. RESULTS: The prevalence of SA in this population of heathcare workers (HCWs) was 35.9% (28/78): 44% of physicians were colonized, 25% of nurses were colonized, 38% of the physician and surgical assistants were colonized, and 33% of the perfusionists were colonized. Of these, 14.3% of isolates were MRSA (5.1% of samples taken). All patient isolates were unique. Although several HCWs shared isolates, their isolates did not match patient isolates. All HCWs with MRSA were decolonized with mupirocin ointment. Based on these results, investigation was focused on best practice in OR prep and antibiotic prophylaxis. LESSONS LEARNED: By culturing HCWs in CS, we identified a high prevalence of MRSA colonization. Although we did not demonstrate transfer of SA from HCW to patient, HCWs should be aware of the potential increase in MRSA colonization.