Nasal carriage of staphylococcus aureus and epidemiology of surgical-site infections in a Sudanese university hospital

Prevalence of Staphylococcus aureus Nasal Carriage in Human Immunodeficiency Virus-Infected and Uninfected Children in Botswana: Prevalence and Risk Factors

AbstractStaphylococcus aureus is an important cause of morbidity and mortality in children in sub-Saharan Africa (SSA). A major risk factor for staphylococcal infection is S. aureus colonization of the anterior nares. We sought to define risk factors for S. aureus carriage and characterize antimicrobial resistance patterns in children in Botswana. A cross-sectional study was conducted at two clinical sites in southern Botswana. Patients under 18 years of age underwent two nasal swabs and brief interviews, 4 weeks apart. Standard microbiological techniques were used. For persistent carriers, S. aureus was isolated from swabs at both time points, and for intermittent carriers, S. aureus was isolated from only one swab. Poisson regression with robust variance estimator was used to compare prevalence of carriage and the resistance phenotypes. Among 56 enrollees, prevalence of S. aureus colonization was 55% (N = 31), of whom 42% (N = 13) were persistent carriers. Of human immunodeficiency virus-infected children, 64% (N = 9) were carriers. Risk factors for nasal carriage included a history of tuberculosis (prevalence ratio [PR] = 1.60; 95% confidence interval [CI] = 1.02, 2.51; P = 0.040) and closer proximity to health care (PR = 0.89; 95% CI = 0.80, 0.99; P = 0.048). Prior pneumonia was more common among persistent rather than intermittent carriers (PR = 2.64; 95% CI = 1.64, 4.23; P < 0.001). Methicillin-resistant S. aureus (MRSA) prevalence was 13%. Of isolates tested, 16% were resistant to three or more drugs (N = 7/44). In summary, children in southern Botswana are frequently colonized with S. aureus. Antibiotic resistance, especially MRSA, is also widespread. Antibiotic recommendations for treatment of staphylococcal infections in SSA should take cognizance of these resistance patterns.

Inducible clindamycin resistance and nasal carriage rates of Staphylococcus aureus among healthcare workers and community members

BACKGROUND

Nasal carriage of Staphylococcus aureus is becoming an increasing problem among healthcare workers and community individuals.

OBJECTIVES

To determine the prevalence of methicillin-resistant S. aureus (MRSA) nasal colonization and inducible clindamycin resistance (ICR) of S. aureus among healthcare workers at Soba University Hospital and community members in Khartoum State, Sudan.

METHODS

Five hundred nasal swabs samples were collected during March 2009 to April 2010. Isolates were identified using conventional laboratory assays and MRSA determined by the disk diffusion method. The D-test was performed for detection of ICR isolates with Clinical Laboratory Standard Institute guidelines.

RESULTS

Of the 114 S. aureus isolated, 20.2% represented MRSA. The occurrence of MRSA was significantly higher among healthcare worker than community individuals [32.7% (18/55) vs. 6.9% (5/59)] (p=0.001). Overall the 114 S. aureus isolates tested for ICR by D-test, 29 (25.4%) yielded inducible resistance. Significantly higher (p=0.026) ICR was detected among MRSA (43.5%) than methicillin-susceptible S. aureus (MSSA) (20.9%).

CONCLUSION

MRSA nasal carriage among healthcare workers needs infection control practice in hospitals to prevent transmission of MRSA. The occurrence of ICR in S. aureus is of a great concern, D- test should be carried out routinely in our hospitals to avoid therapeutic failure.

Staphylococcus aureus bacteremia: targeting the source

Bacteremia due to Staphylococcus aureus is one of the major causes of morbidity and mortality in India, but studies targeting the source of Staphylococcus aureus bacteremia are lacking. S. aureus has a vivid armamentarium consisting of toxins, adhesins, and other virulence factors by virtue of which it can cause varied types of infections, sometimes of a serious nature. This review highlights the possible causes of S. aureus bacteremia, and discusses the necessity of tracing its source and eliminating it with proper antibiotic therapy to avoid recurrences or relapses.

Y, El-Sayed AS, Abdel-Rahman ME. Prophylactic antibiotics and wound infection

INTRODUCTION

Surgical site infections account for 14%-25% of all nosocomial infections. The main aims of this study were to audit the use of prophylactic antibiotic, to quantify the rate of post-operative wound infection, and to identify risk factors for its occurrence in general surgery.

METHODOLOGY

A cross-sectional study was conducted in the General Surgery Department in Khartoum Teaching Hospital- Sudan. All Adult patients (age ≥18 years) admitted during March 1(st) to 31(st) October 2010 were recruited. Multivariable logistic analysis was done to identify wound infection risk factors. Prescriptions were audited against predetermined criteria.

RESULTS

A total of 540 patients were recruited; (females73.7% of total ). The performed surgical procedures were 547. The rate of wound infection was 10.9%. Multivariable logistic analysis showed that; ASA score ≥ 3; (p= <0.001), wound class (p= 0.001), and laparoscopic surgical technique; (p= 0.002) were significantly associated with prevalence of wound infection. Surgical prophylaxis was unnecessarily given to 311 (97.5%) of 319 patients for whom it was not recommended. Prophylaxis was recommended for 221 patients; of them 218 (98.6 %) were given preoperative dose in the operating rooms. Evaluation of prescriptions for those patients showed that; spectrum of antibiotic was adequate for 160 (73.4%) patients, 143 (65.6%) were given accurate doses, only 4 (1.8%) had the first preoperative dose/s in proper time window, and for 186 (85.3%) of them prophylaxis was extended post-operatively. Only 36 (6.7%) prescriptions were found to be complying with the stated criteria.

CONCLUSION

The rate of wound infection was high and prophylactic antibiotics were irrationally used. Multiple interventions are needed to correct the situation.

Prevalence of nasal carriage and diversity of Staphylococcus aureus among inpatients and hospital staff at Korle Bu Teaching Hospital, Ghana

There is a paucity of data on Staphylococcus aureus epidemiology in Africa. Prevalence of nasal carriage and genetic diversity of S. aureus were determined among hospital staff (HS) and inpatients (IP) at the largest hospital in Ghana. In total, 632 nasal swabs were obtained from 452 IP and 180 HS in the Child Health Department (CHD) and Surgical Department (SD). S. aureus carriage prevalences were 13.9% in IP and 23.3% in HS. The chance of being a carrier was higher in HS (P=0.005) and IP staying ≤7 days in hospital (P=0.007). Resistance to penicillin (93%), tetracycline (28%) and fusidic acid (12%) was more common than for other agents (<5%). A higher chance of multidrug-resistant S. aureus carriage was observed among IP compared with HS (P=0.01). High genetic diversity was shown by spa typing, with 55 spa types found among 105 isolates; the predominant spa types were t355 (10%) and t084 (10%). MRSA was detected in six IP with an overall carriage prevalence of ca. 1.3%, but not in HS. All three MRSA isolates from SD belonged to ST88-SCCmec IV, and two of them displayed the same spa type and antibiograms; three MRSA isolates from CHD belonged to distinct lineages (ST88-SCCmec IV, ST8-SCCmec V and ST72-SCCmec V). Altogether, these data indicate a high diversity of S. aureus, low levels of MRSA carriage, and a higher chance of nasal carriage of multidrug-resistant S. aureus among IP compared with HS in this hospital.

Pattern of pathogens and their sensitivity isolated from surgical site infections at the Aga Khan University Hospital, Nairobi, Kenya

BACKGROUND

In low income countries, surgical site infections (SSIs) are costly and impose a heavy and potentially preventable burden on both patients and healthcare providers. This study aimed to determine the occurrence of SSI, pathogens associated with SSI, the antibiogram of the causative pathogens and specific risk factors associated with SSI at the hospital.

METHODS

Two hundred and sixty-eight respondents admitted for general surgical procedures (other than neurological and cardiothoracic surgeries) at the Aga Khan University Hospital were eligible to take part in the study. Post-surgery patients were observed for symptoms of infection. Follow ups were done through the consulting clinics, breast clinic and casualty dressing clinic by a team of surgeons. In cases of infection, pus swabs were collected for culture.

RESULTS

SSI incidence rate was 7.0%, pathogens isolated from SSI included gram negative enteric bacilli and S. aureus which was the most prevalent bacterial isolate. Only one isolate of MRSA was found and all staphylococci were susceptible to Vancomycin. Preoperative stay ≥ 2 days and wound class were the risk factors associated with SSI.

CONCLUSION

The SSI incidence rates (7.0%) observed in this study were relatively lower than the ones documented in other studies in Kenya. S. aureus is the most prevalent pathogen associated with SSI. Similar to findings from other studies done in the region; prolonged hospital stay and dirty wounds were the risks associated with postsurgical sepsis at the hospital.

Staphylococcus aureus nasal carriage in a Moroccan dialysis center and isolates characterization

Staphylococcus aureus, which has its ecological niche in the anterior nares, has been shown to cause a variety of infectious diseases mainly for patients in hemodialysis units. We performed this study to evaluate the prevalence of nasal S. aureus carriage among hemodialysis outpatients, to determine the antimicrobial susceptibility of isolates, to characterize the virulence genes, and to identify associated risk factors. Nares swab specimens were obtained from 70 outpatients on hemodialysis between March and June 2010. Samples were plated immediately onto S. aureus specific media and pattern of antibacterial sensitivity was determined using disk diffusion method. Polymerase chain reaction was used to detect nuc, mecA, and genes encoding staphylococcal toxins. Medical record of patients was explored to determine S.aureus carriage risk factors. Nasal screening identified 42.9% S. aureus carriers with only one (3.3%) methicillin-resistant S. aureus isolate. Among the methicillin-susceptible S. aureus isolates, high rate of penicillin resistance (81.8%) has been detected. The identified risk factors were male gender and age ≤ 30 years. Research of virulence factors showed a high genetic diversity among the 30 S. aureus isolates. Twenty-one (70%) of them had at least one virulence gene, of which 3.3% were Panton-Valentine leukocidin (lukS/F-PV) genes. S. aureus carriage must be screened for at regular intervals in hemodialysis patients. Setting up a bacterial surveillance system is one of the strategies to understand the epidemiology of methicillin-resistant S. aureus, to guide local antibiotic policy and prevent spread of antibiotic-resistant S. aureus.

Prevalence of bacterial contamination in general operating theaters in selected hospitals in the Gaza Strip, Palestine

OBJECTIVES

This study was conducted in general operating theaters at public and private hospitals in the Gaza Strip, Palestine to determine the prevalence of bacterial contamination of different objects.

METHODS

Swabs were collected from 21 items that were distributed over three categories (equipment, environment and personnel). In total, 243 swabs were collected at pre- and post-operation stages and were cultured and identified using standard microbiological procedures.

RESULTS

The results show that 24.7% of the swabs were contaminated with microorganisms. The equipment, environment and personnel were responsible for 45%, 48.3% and 6.7% of contamination, respectively. The rate (26.9%) of contamination in the post-operation samples was higher than in the pre-operation samples (22.6%), but the difference was not statistically significant. In addition, there was not a statistically significant increase in the prevalence of contamination in private (28.7%) compared to public hospitals (21.8%). Of the seven bacterial genera that were recovered, the highest percentage belonged to Staphylococcus spp. (45.3%) followed by Enterobacter spp. (23.4%).

CONCLUSIONS

This study reveals a moderate percentage of contamination in our public and private hospital general operating theaters, which may increase the risk factors for developing surgical-site infections. These observations justify more attention being paid to infection-control efforts in our hospitals.

Cluster-randomized, crossover trial of the efficacy of plain soap and water versus alcohol-based rub for surgical hand preparation in a rural hospital in Kenya

Background

The aim of this cluster-randomized, crossover trial was to compare the efficacy of plain soap and water with an alcohol-based handrub for surgical hand preparation and prevention of surgical-site infection (SSI) in a Kenyan rural hospital.

Methods

A total of 3317 patients undergoing clean and clean-contaminated surgery were included. Follow-up data 30 days after discharge were available for 3133 patients (94·5 per cent).

Results

SSI occurred in 255 patients (8·1 per cent), with similar rates for both study arms: 8·3 per cent for alcohol-based handrub versus 8·0 per cent for plain soap and water (odds ratio 1·03, 95 per cent confidence interval 0·80 to 1·33). After adjustment for imbalances between study arms and clustering effects, the main outcome measure remained unchanged (adjusted odds ratio 1·06, 0·81 to 1·38). The duration of surgery and wound contamination class independently predicted SSI. The cost difference between the methods was small (€4·60 per week for alcohol-based handrub compared with €3·30 for soap and water).

Conclusion

There was no statistically or clinically significant difference in SSI rates, probably because more important factors contribute to SSI development. However, this study demonstrated the feasibility and affordability of alcohol-based handrubs for hand preparation before surgery in settings without continuous, clean water. Registration number: NCT00987402 (http://www.clinicaltrials.gov).

Bacteriological and parasitological assessment of food handlers in the Omdurman area of Sudan

BACKGROUND/PURPOSE

Pathogenic organisms are thought to be widely distributed among food handlers. This study was designed to assess the prevalence of carriers of some pathogenic bacteria and intestinal parasites among food handlers in the city of Omdurman, Sudan.

METHODS

A total of 518 nasal swabs and stool specimens were collected. Nasal swabs were cultured on bacteriological culture media. Stool specimens were examined microscopically for intestinal parasites.

RESULTS

Of the total subjects examined, 30.1% were found to be carriers of pathogenic organisms. The pathogens isolated and identified were the bacteria Staphylococcus aureus, Salmonella typhi, and Shigella boydii, and the intestinal parasites, Giardia lamblia and Entamoeba histolytica/dispar. Bacteria and intestinal parasites were most prevalent among storekeepers (41%), followed by restaurant workers (24.4%), bakers (24.4%), butchers (5.1%), milk distributors (2.6%), and fruits/vegetables sellers (2.6%). S. aureus, the most abundant pathogen, was most prevalent in storekeepers (44.6%), followed by restaurant workers (25%), bakers (17.9%), butchers (5.4%), milk distributors (3.6%), and fruit/vegetable sellers (3.6%).

CONCLUSION

The findings from this study indicate a key role for food handlers in the spread and transmission of food communicable diseases and reveal the need for protective measures.

Molecular fingerprinting of meticillin-resistant Staphylococcus aureus strains isolated from patients and staff of two Iranian hospitals

Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of hospital-acquired infection. Methods for typing and epidemiological investigation of MRSA isolates have an important impact in detection of MRSA strains, source, transmission and control of these micro-organisms. The aims of this study were to study molecular diversity of MRSA isolates by randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR), the surveillance efficacy of this method and determination of antibiotic resistance patterns of MRSA isolates. MRSA isolates were collected from clinical specimens and noses of 460 staff and inpatients admitted to Imam Khomeini and Paediatric Hospitals during a six-month period (2004-2005). Eighty MRSA strains, in which the presence of mecA gene had been confirmed by PCR, were subjected to RAPD-PCR using five primers and the results were summarised in a dendrogram to show the relationships between the test isolates. Antibiotic resistance patterns of MRSA isolates were also determined by disc agar diffusion method using 13 antibiotic discs according to Clinical and Laboratory Standards Institute guidelines. Forty-three RAPD-PCR profiles were detected. The test isolates were clustered into 18 taxa with 50% similarity, indicating the heterogeneity of our test isolates. MRSA isolates fell into 41 antibiotic resistance patterns. There was correlation between antibiotic resistance patterns and results of RAPD-PCR. Most of the MRSA isolates were multi-resistant.

Staphylococcus aureus transmission through oronasal fistula in children with cleft lip and palate

OBJECTIVE

To determine the presence of Staphylococcus aureus in a nasal flora and oral environment, the correlation between frequency of transmission of S. aureus and oronasal fistula size, and the pattern of methicillin resistance on S. aureus strains in children with cleft lip and palate (CLP).

DESIGN

Thirty-two CLP children with and without oronasal fistulas, ranging in age from 5 to 13 years were examined for oronasal fistula presence and size. Stimulated saliva samples and nasal swab samples were taken and investigated for S. aureus presence. S. aureus presence and counts were correlated with fistula presence and size.

RESULTS

Saliva samples showed statistical differences between the groups with and without oronasal fistulas with an area ranging from 0.80 to 28.26 mm2. The S. aureus counts were significantly higher (r = .535, p = .002) in saliva samples from children with larger oronasal fistula. The S. aureus count was not significantly different (r = -.013, p = .942) in nasal samples compared with oronasal fistula size. Methicillin resistance with disk-diffusion method was recorded as sensitive (> or =13 mm) in all S. aureus strains.

CONCLUSIONS

The results of this study indicate a positive correlation between fistula size and S. aureus transmission to one oral environment through oronasal fistulae, and a positive correlation between frequency of S. aureus transmission and fistula size. All S. aureus strains were sensitive to methicillin. These results may have implications for preventive treatment of CLP children.

Staphylococcus aureus isolates from Irish domestic refrigerators possess novel enterotoxin and enterotoxin-like genes and are clonal in nature

A previous study carried out by the National Food Centre in Dublin on bacterial contamination of Irish domestic refrigeration systems revealed that 41% were contaminated with Staphylococcus aureus. One hundred fifty-seven S. aureus isolates were screened by multiplex PCR analysis for the presence of 15 staphylococcal enterotoxin and enterotoxin-like genes (sea-see, seg-sei, selj-selo, and selq) and the toxic shock toxin superantigen tst gene. Of the refrigerator isolates, 64.3% possessed more than one staphylococcal enterotoxin or staphylococcal enterotoxin-like gene. All bar one of the 101 staphylococcal enterotoxin or staphylococcal enterotoxin-like gene-positive strains possessed the egc locus bearing the seg, sei, selm, seln, and selo genes. Twelve random amplified polymorphic DNA (RAPD) types accounted for 119 (75.8%) of the strains, two of these types accounting for 25 (RAPD type 1, 15.9%) and 52 (RAPD type 5, 33.1%), respectively. All of the RAPD type 5 isolates possessed the egc gene cluster only. The RAPD type 5 amplicon profile was identical to that of S. aureus isolates associated with osteomyelitis in broiler chickens in Northern Ireland that also possessed the egc locus only. However, the RAPD type 5 domestic refrigerator and chicken isolates differed in penicillin G sensitivity, production of Protein A and staphylokinase, and crystal violet agar growth type. These findings highlight that the average Irish household refrigerator harbors potential enterotoxin-producing S. aureus that may or may not be of animal origin and, accordingly, is a potential reservoir for staphylococcal food poisoning.

Differences between Staphylococcus aureus isolates from medical and nonmedical hospital personnel

It is unclear whether the levels of Staphylococcus aureus colonization of hospital personnel with patient exposure are increased or whether personnel become colonized with more antibiotic-resistant strains. Differences in nasal and hand carriage of S. aureus between medical and nonmedical hospital personnel were examined. No differences in nasal carriage between the two groups were found; however, there was a trend that suggested differences in the rates of hand carriage of S. aureus (18% of nonmedical personnel and 10% of medical personnel). Medical personnel were colonized with more antibiotic-resistant isolates than nonmedical personnel (mean, 2.8 versus 2.1 isolates [P < 0.03]), and the strain profiles indicated that they tended to be more clonal in origin, suggesting that exposure to hospital isolates alters the colonization profile.

Epidemiological study of staphylococcal colonization and cross-infection in two West African Hospitals

Surveillance in two medium-size (250-300 beds) hospitals located in the most populated islands of Cape Verde was undertaken in July 1997 in order to obtain data concerning nasal carriage of staphylococci. Nasal swabs (172) taken from inpatients and health care workers (HCW) from different internment services yielded 68 Staphylococcus aureus and 105 coagulase-negative staphylococcal (CNS) isolates, demonstrating extensive colonization of both inpatients and HCW by S. aureus (carriage rate 41%) and CNS (carriage rate 65%). The most frequent CNS species were S. epidermidis and S. haemolyticus. Three species--S. aureus, S. epidermidis, and S. sciuri-were recovered from wound swabs. The antibiotic susceptibility profiles of S. aureus and CNS differed sharply: all 68 S. aureus were resistant to penicillin but were fully susceptible to oxacillin as well as the other antimicrobial agents tested-gentamicin; erythromycin, except for three strains; ciprofloxacin; sulfamethoxazole-trimethoprim, except for two strains; vancomycin; and amoxicillin/clavulanate. In contrast, most (91/105) of CNS were resistant to both penicillin and oxacillin, and a variable but substantial proportion of CNS isolates also carried multiresistant traits to gentamicin, erythromycin, sulfamethoxazole-trimethoprim, and amoxicillin/clavulanate. The analysis by PFGE of the methicillin-susceptible S. aureus (MSSA) and the methicillin-resistant S. epidermidis (MRSE) strains provided evidence for extensive cross-infection and cross-colonization from HCW to patients.

An epidemiological study on the occurrence of Staphylococcus aureus in superficial abscesses of patients presenting for surgery in a teaching hospital in Khartoum, Sudan

A group of patients (n=86) suffering from superficial abscesses was recruited in the Khartoum Teaching Hospital, Sudan. Detailed clinical and socio-economic data were collected. It appeared that 83% of all patients were younger than 40. Labourers were most prevalent (28%), followed by students (23%) and housewives (16%). The head and neck were most often affected (22%), with hands being second (19%). In 92% of all pus cultures a microbial agents was identified, the large majority being Staphylococcus aureus (69%). Among patients, 47% were nasal carriers of S. aureus, similar to the carriage rate measured among controls, suggesting that nasal carriage is no risk factor for abscess development. Multivariate logistic regression analysis revealed that a history of abscess, recent traditional medical treatment, poor hygiene and low socio-economic status were significantly and independently associated with the occurrence of superficial abscesses.