Israel Medical Association Journal

Background: Antibiotic resistance is a worldwide problem associated with increased morbidity and mortality.

Objectives: To evaluate multidrug resistant (MDR) bacteria carriage in selected populations.

Methods: Data were collected from all patients under 18 years who met our internal guidelines from 2015–2016. They were screened for carbapenem-resistant Enterobacteriaceae (CRE), extended spectrum beta-actamase (ESBL), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococci (VRE). Indications for screening were non-resident non-Israeli patients (from the Palestinian Authority, Syria, and foreign patients), internal transfers from intensive care units, admission to high-risk departments, recent carriage of MDR bacteria, transfer from other hospitals, and recent hospitalization. Data were analyzed for MDR bacteria from at least one screening site (rectal, nasal, axillary, groin, throat). All data were analyzed per patient and per sample.

Results: During the study period 185/2632 positive screening sets (7%) were obtained from 725 patients. Of these, 165 patients (22.7%) were positive for at least one pathogen. Significantly fewer Israeli residents (120/615, 19.5%) tested positive compared to non-Israeli residents (45/110, 40.9%; P < 0.001). Past MDR bacteria carriage was the only significant screening indication (25/61, 41%; P < 0.001). CRE, VRE, MRSA, and ESBL prevalence rates were 0.6% (5/771), 0.5% (3/560) 0.5%, 4.2% (37/888), and 33.7% (139/413), respectively. Among non-ESBL carriers, MRSA was predominant with 38 positive cultures (n=34).

Conclusions: Non-Israeli non-residents and patients with previous positive MDR screening are at higher risk for MDR bacteria. Indications used to identify high-risk patients for drug resistant pathogens were efficacious. More effort is needed to reduce excessive sampling.

Background: The hepatobiliary system is a sterile micro-environment. Bacterial infection in this system is most commonly associated with anaerobes as well as gram-positive and gram-negative bacteria. Biliary infections with Staphylococcus aureus are poorly characterized.

Objectives: To depict the clinical characteristics and outcome of patients with S. aureus infection of the hepatobiliary system.

Methods: Medical records of patients with bile cultures positive for S. aureus from January 2006 to November 2020 were extracted from the computerized database of a hospital in Israel.

Results: We analyzed the results of 28 cases that were found in the database. The mean age of study patients was 62.2 ± 19 years. Hypertension, dyslipidemia, chronic kidney disease, diabetes, and benign prostatic hypertrophy were the most common co-morbidities (57.1%, 32.1%, 25%, 25%, and 25%, respectively). Fourteen of the methicillin-resistant S. aureus (MRSA) bile cultures (82.3%) were a result of primary S. aureus biliary infections (no other source for S. aureus infection) and the remainder were of a secondary infection. Eight of the MRSA cultures (47.1%) were from hospital acquired infections. Increased hospital mortality in patients with S. aureus hepatobiliary infection was associated with hypertension (P = 0.04), bedridden status (P = 0.01), and nursing home residence (P = 0.003).

Conclusions: Hepatobiliary infection with S. aureus can manifest in a variety of ways. S. aureus should be especially considered in patients who are bedridden, present with hypertension, or live in nursing homes because of their association with in-hospital mortality resulting from this entity.

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a challenging nosocomial pathogen in the last 50 years.

Objectives: To describe an investigation and containment of an MRSA outbreak in a neonatal intensive care unit (NICU).

Methods: Our NICU is a 25-bed level III unit. Almost 540 neonates are admitted yearly. The index case was an 8 day old term baby. MRSA was isolated from his conjunctiva. Immediate infection control measures were instituted, including separation of MRSA+ carriers, strict isolation, separate nursing teams, and screening of all infants for MRSA. Healthcare workers and parents of positive cases were screened and re-educated in infection control measures. New admissions were accepted to a clean room and visiting was restricted. MRSA isolates were collected for molecular testing.

Results: MRSA was isolated from five infants by nasal and rectal swabs, including the index case. Screening of healthcare workers and families was negative. Two MRSA+ patients already known in the pediatric intensive care unit (PICU) located near the NICU were suspected of being the source. All NICU isolates were identical by pulsed-field gel electrophoresis but were different from the two PICU isolates. The NICU and one of the PICU isolates were defined as ST-5 strain by multilocus sequence typing. One PICU isolate was ST-627. All NICU isolates were Panton–Valentine leukocidin negative and SCCmec type IV. No further cases were detected, and no active infections occurred.

Conclusions: A strict infection control policy and active screening are essential in aborting outbreaks of MRSA in the NICU.

Background: Isolation of methicillin-resistant Staphylococcus aureus (MRSA) in healthy individuals is not common in Israel. In our hospital, about 30% of MRSA isolates were SCCmec types IV and V.

Objectives: To identify the demographic and clinical characteristics of patients carrying MRSA SCCmec type IV or V, and to compare them with each other and with those of patients with SCCmec types I-III.

Methods: We conducted a case-control study that included 501 patients from whom MRSA was isolated: 254 with SCCmec type I, II, or III, and 243 isolates from SCCmec types IV or V. 

Results: MRSA was isolated from surveillance cultures in 75% of patients and from a clinical site in 25%. The majority of our study population was elderly, from nursing homes, and with extensive exposure to health care. First, we compared characteristics of patients identified through screening. Statistically significant predictors of SCCmec V vs. IV were Arab ethnicity (OR 7.44, 95%CI 1.5–37.9) and hospitalization in the year prior to study inclusion (OR 5.7, 95%CI 1.9–16.9). No differences were found between patients with SCCmec types I-III and patients with SCCmec type IV or V. Analysis of the subset of patients who had clinical cultures yielded similar results. 

Conclusions: SCCmec types IV and V were common in the hospital setting although rare in the community. It seems that in Israel, SCCmec IV and V are predominantly health care-associated MRSA. 

 

Background: The compliance of hospital staff with guidelines for the active surveillance of methicillin-resistant Staphylococcus aureus (MRSA) in Israel has not been determined.

Objectives: To evaluate the compliance of hospital staff with guidelines for the active surveillance of MRSA and assess its impact on the incidence of nosocomial MRSA bacteremia.

Methods: We assessed compliance with MRSA surveillance guidelines by assessing adherence to the screening protocol and reviewing medical and nursing charts of patients colonized with MRSA, and observed hand hygiene opportunities among health care workers and colonized patients. Rates of nosocomial MRSA bacteremia and of adherence with hand hygiene among overall hospital staff were obtained from archived data for the period 2001–2010.

Results: Only 32.4% of eligible patients were screened for MRSA carriage on admission, and 69.9% of MRSA carriers did not receive any eradication treatment. The mean rate of adherence to glove use among nurses and doctors was 69% and 31% respectively (P < 0.01) and to hand hygiene 59% and 41% respectively (P < 0.01). The hospital overall rate of adherence to hand hygiene increased from 42.3% in 2005 to 68.1% in 2010. Rates of nosocomial MRSA bacteremia decreased by 79.2%, from 0.48 (in 2001) to 0.1 (in 2010) per 1000 admissions (P < 0.001).

Conclusions: The compliance of medical and nursing staff with guidelines for active MRSA surveillance was poor. The encouraging increase in adherence to hand hygiene and concomitant decrease in nosocomial MRSA bacteremia is gratifying. The deficiencies in compliance with MRSA infection control policy warrant an adjusted strategy based on the hospital resources.

Background: Staphylococcus aureus infection is a major cause of morbidity and mortality worldwide. Clindamycin is widely used in the treatment of staphylococcal infections; however, it is our impression that in the last few years, inducible clindamycin resistance (ICR) has become more prevalent.

Objective: To assess the prevalence of ICR[1] in methicillin-sensitive Staphylococcus aureus (MSSA) infections among pediatric patients in Israel.

Methods: We reviewed the files of children diagnosed with MSSA[2] infections during the period January 2006 to June 2007 for full antibiogram (including the D-test for ICR), phage typing and randomly amplified polymorphic DNA.

Results: Altogether, 240 MSSA isolates were recovered, mainly from wounds and abscesses. ICR was detected in 62 of 68 erythromycin-resistant/clindamycin-sensitive strains (91%); the ICR rate for the total number of isolates was 26% (62/240). Phage type analysis demonstrated that 38 of 61 ICR isolates

(62%) were sensitive to group 2, compared to 42 of 172 isolates (24%) that did not express ICR (P < 0.01). On randomly amplified polymorphic DNA, phage type 2 isolates expressing ICR belonged to the same clone, which was different from ICR isolates sensitive to other phages and from isolates not expressing ICR.

Conclusions: Inducible clindamycin resistance is common among methicillin-sensitive Staphylococcus aureus in Israeli children. The D-test should be performed routinely in all isolates of MSSA.

Objectives: To test the in vitro activity of linezolid (oxazolidinone) and other antimicrobial agents against MRSA[1] isolates recovered from hospitalized patients.

Methods: We tested 150 MRSA isolates recovered from hospitalized patients. The minimal inhibitory concentration of vancomycin, teicoplanin, pristinamycin (quinupristin-dalforistin), and linezolid was determined by the Etest method. Susceptibility to other antibiotics was tested by the disk diffusion method.

Results: All isolates were sensitive to vancomycin, teicoplanin, pristinamycin, and linezolid. The MIC₉₀ was 2.0 mg/ml for vancomycin and teicoplanin (range 0.5–2.0 mg/ml and 0.125–2.0 mg/ml, respectively), and 0.5 mg/ml for pristinamycin and linezolid (range 0.125–0.75 mg/ml and 0.125–0.5 mg/m, respectively). Of the other antibiotics, fusidic acid showed the best in vitro activity, with 96.7% susceptibility, associated with trimethoprim/sulfamethoxazole (85.8%) and minocycline (84%). Penicillin was associated with the lowest susceptibility (1.3%), associated with ofloxacin (3%) and erythromycin (14%). An increase in the minimal inhibitory concentration value of vancomycin was associated with a significant decrease in resistance to TMP-SMZ[2] (P < 0.01) and an apparent increase in resistance to other antibiotics.

Conclusion: The excellent in vitro activity of linezolid and its reported in vivo effectiveness renders it an important therapeutic alternative to vancomycin in the treatment of MRSA infection.

__________________

[1] MRSA = methicillin-resistant Staphylococcus aureus

[2] TMP-SMX = trimethoprim/sulfamethoxazole

Background: Nasal colonization with methicillin-resistant Staphylococcus aureus in the community is being increasingly reported, but there is a general lack of data on MRSA[1] colonization in children in chronic care institutions and on colonization rates in Israeli children.

Objectives: To define the rate of MRSA nasal colonization in a generally healthy pediatric population in Jerusalem, to compare it with that of children in chronic care institutions, to define risk factors for colonization, and to compare community and hospital-acquired MRSA strains.

Methods: Anterior nares culture for the presence of methicillin-sensitive and methicillin-resistant S. aureus was taken from 831 healthy children attending primary pediatric clinics or emergency department and 118 children hospitalized in three chronic care institutions in Jerusalem.

Results: Of the 831 healthy children, 195 (23.5%) were colonized with S. aureus, as compared to 43 of 118 (36.4%) chronically institutionalized children (P < 0.005). Five of the 195 S. aureus isolates from healthy children (2.6%) were MRSA, as compared to 9 of 43 (21%) from chronically institutionalized children (P < 0.001). Older age and a family member who is a healthcare worker were associated with S. aureus colonization in the population of healthy children, and older age was associated with MRSA colonization in the chronically institutionalized children. The antibiotic susceptibility pattern was similar for both groups, and pulsed field gel electrophoresis of the isolates showed a wide and random distribution in both groups.

Conclusions: MRSA colonization in the studied pediatric community in Jerusalem was very low, whereas that of patients hospitalized in chronic care institutions was significantly higher. In the small number of isolates detected, no significant differences were found in antibiotic susceptibility or PFGE[2] pattern between hospital-acquired and community-acquired strains.