COVID-19 vaccine breakthrough infection among health care workers at MODHS hospitals in Saudi Arabia: A multicenter study.

BACKGROUND: We investigated the clinical manifestation and severity of COVID-19 infection represented as a composite outcome (hospital or ICU admission, or in-hospital death) among infected fully vaccinated HCWs, the RT-PCR test Ct value (Cycle Threshold) of positive fully vaccinated HCWs, and we measure the interval from the second vaccine to acquiring the infection. METHODS: A multicenter retrospective cohort study was conducted in different regions at (16) Ministry of Defense Health Services (MODHS) hospitals. Data were restricted to fully vaccinated (minimum of 2 doses) HCWs who had a confirmed positive PCR test and employed in MODHS hospitals from August 2021 to March 2022. RESULTS: A total of 45862 HCWs were vaccinated as of Aug 2021. Of these 1253 participants met the selection criteria and were included in the study. The average age of infected HCWs was 35.27 years (SD = ± 8.10) of which 57% were females. The HCWs were employed as doctors (24%), nurses (33%), and other (43%). The most administered vaccine type was mRNA (44%) followed by Adenovirus Viral Vector (39%) and mixed vaccine (17%). The incidence of COVID-19 vaccine breakthrough (BT) infection among HCWs was observed at 2.73% (m-RNA 3.19%, Viral Vector 2.83% and mixed 1.87%). CONCLUSION: the overall COVID-19 (BT) infection incidence proportion was (2.73%), with the Mixed vaccine group showing the lowest (BT) incidence proportion (1.87%). The most commonly reported symptoms among (BT) infections were cough (51%), sore throat (51%), fever (47%), headache (31%), and runny nose (23%), with overall (6%) asymptomatic (BT) infections. We had (1%) hospital admissions, Zero ICU admission, and Zero deaths. our finding may indicate that infection affecting fully vaccinated patients were less severe and mostly affected the upper respiratory tract.

Self-reported long COVID-19 symptoms are rare among vaccinated healthcare workers.

INTRODUCTION: COVID-19 pandemic adversely affected healthcare workers (HCWs). Here, we evaluate the occurence of long-COVID-19 symtoms among HCWs. METHODS: This is a questionnaire-based study of HCWs who had COVID-19 in two medical centers in Saudi Arabia and were mostly vaccinated. RESULTS: The study included 243 HCWs with a mean age (+ SD) of 36.1 (+ 7.6) years. Of them, 223 (91.8%) had three doses of COVID-19 vaccine, 12 (4.9%) had four doses, and 5 (2.1%) had two doses. The most common symptoms at the start of the illness were cough (180, 74.1%), shortness of breath (124, 51%), muscle ache (117, 48.1%), headache (113, 46.5%), sore throat (111, 45.7%), diarrhea (109, 44.9%) and loss of taste (108, 44.4%). Symptoms lasted for< one week in 117 (48.1%),> one week and< 1 month in 89 (36.6%),> 2 months and< 3 months in 9 (3.7%), and> 3 months in 15 (6.2%). The main symptoms present> 3 months were hair loss (8, 3.3%), cough (5, 2.1%), and diarrhea (5, 2.1%). A binomial regression analysis showed no relationship between persistence of symptoms for> 3 months and other demographic or clinical symptoms characteristics. CONCLUSION: The study showed a low rate of the occurence of long-COVID> 3 months during the Omicron-wave among mostly vaccinated HCWs with no significant comorbidities. Furhter studies are needed to examine the effect of different vaccines on long-COVID-19 among HCWs.

COVID-19 vaccine had a significant positive impact on patients with SARS-COV-2 during the third (Omicron) wave in Saudi Arabia.

INTRODUCTION: The third (Omicron) wave had caused significant increase in the number of COVID-19 cases around the globe. The severity of the disease dependeds on the extent of the vaccination status. METHODS: This is a retrospective study of infected COVID-19 patients during the third (Omicron) wave in a hospital in Saudi Arabia. RESULTS: A total of 400 patients were included with 220 (55 %) males and 180 (45 %) females, and a mean age (+/- SD) of 36.34 + 16.47 years. The most common presenting symptoms were: sore throat 159 (39.8 %), cough 158 (39.5 %), fever 132 (33 %), headache 122 (30.5 %), and muscle ache 124 (31%). There was no difference in underlying conditions, signs and symptoms between males and females apart from the occurrence of sore throat with an OR of 2.014 (95 % CI: 1.103-3.677, P = 0.023) and need of hospitalization OR 2.457 (95 % CI: 1.168-5.167, P value =.018) in a binary logistic regression comparison. The need for hospitalization was inversely related to the number of COVID-19 vaccination doses. The rate of admission was 8 (72.7 %), 34 (12 %), 4 (5.4 %) for one, two, and three doses of COVID-19 vaccine, respectively (P < 0.0001). Of all the patients, 14 (3.5 %) and 8 (2 %) required intensive care (ICU) admission and mechanical ventilation, respectively. The median Ct-value of SARS-CoV-2 was higher in those who had 2 or 3 doses compared to those who had one dose of the COVID-19 vaccine, but the difference did not reach statistical significance. None of the included patients died during the study period. CONCLUSION: Omicron variant symptoms among infected patients are generally milder compared to other variants. Prior COVID-19 vaccination may limit disease severity and need for hospitalization.

Antimicrobial resistance trends of non-fermenter Gram negative bacteria in Saudi Arabia: A six-year national study.

BACKGROUND: Antimicrobial resistance (AMR) of non-fermenting Gram-negative bacteria (NFGNB) is increasingly recognized as urgent healthcare threat. Trend data on AMR of NFGNB in Saudi Arabia are either old or limited. The objective was to estimate the prevalence and resistance trends of isolated NFGNB in Saudi Arabia. METHODS: A retrospective multicenter study involving seven tertiary care hospitals in Saudi Arabia was conducted between 2011 and 2016. Susceptibility testing for non-duplicate isolates was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines in College of American Pathologists accredited diagnostic microbiology laboratories in the participating hospitals. RESULTS: Out of 461,274 isolates, 100,132 (21.7%) were NFGNB which represented 30% of gram-negative pathogens. Pseudomonas aeruginosa was the most common (73.6%), followed by Acinetobacter baumannii (21.0%) and Stenotrophomonas maltophilia (5.3%). Resistance trends of P. aeruginosa were increasing for aztreonam (absolute increase during the study was 17.3%), imipenem (12.3%), and meropenem (11.6%). A. baumannii was fully resistant to several beta lactam drugs, and resistance trends were increasing for potential treatments such as tigecycline (25.1%) and tobramycin (15.5%). S. maltophilia was >90% resistant to trimethoprim/ sulfamethoxazole and ciprofloxacin by the end of the study. CONCLUSION: We are reporting high and/or increasing resistance of NFGNB to common treatment options. The current findings call for urgent actions to combat the increasing resistance of NFGNB. Large scale sharing of AMR data collected at different hospitals with the Saudi AMR committee would be critical to set priorities and monitor progress.

Safety and Reactogenicity of the ChAdOx1 (AZD1222) COVID-19 Vaccine in Saudi Arabia.

INTRODUCTION: The Kingdom of Saudi Arabia was one of the first countries to implement a COVID-19 vaccination program. This study estimated the safety and reactogenicity of the ChAdOx1-S vaccine after the first dose administered to adults. METHODS: This cross-sectional study included 1592 randomly selected vaccinees from April to May 2021. A questionnaire was delivered to the vaccinees via phone calls 7 and 21 days after the first vaccine dose. RESULTS: Of the 1592 vaccinees who had the first dose, the mean age was 37.4 (± 9.6) years and 81% were males. Of all the vaccinees, 553 (34.7%) reported an adverse reaction on the first telephone call. The most common symptoms were: pain at the site of injection (485, 30.5%), musculoskeletal symptoms (438, 27.5%), skin rash (307, 19.2%), gastrointestinal symptoms (379, 23.8%) and fever (498, 31.3%). Men were more likely to report fever (76.9% vs. 23.1%; P = 0.005), skin rash (81.1% vs. 18.9%, P = 0.005) and pain at the injection site (77.3% vs. 22.7%, P < 0.0001). Post-vaccine COVID-19 infection was 0.5% and there were no hospitalizations. CONCLUSION: This study observed no major side effects of the ChAdOx1-S vaccine and no reported breakthrough infection during the observation period.

Abdominal tuberculosis in a tertiary care centre in Saudi Arabia.

OBJECTIVES: Abdominal tuberculosis (ATB) is the second most common type of extra-pulmonary tuberculosis. Though it does not usually pose a significant risk of infectivity, ATB can go unidentified and progress to disseminated infection. The aim of this study is to highlight the incidence and outcome of this infection in a tertiary care centre in the Kingdom of Saudi Arabia (KSA). METHODS: In this retrospective study, we included all ATB patients admitted to our centre between January 1 st, 2010 and December 31, 2018. A total of 42 patients with a median age of 49 (range 18-83 years, 78.6% males) were identified. RESULTS: The most common presentation was abdominal pain, weight loss, and abdominal distension. All the patients were HIV negative; however, 50% had a comorbid condition, mainly diabetes mellitus, chronic renal failure, and liver cirrhosis. Tuberculous peritonitis was the predominant type of ATB. Suspicious and potentially malignant abdominal masses appeared on the abdominal CT scans of six patients. This suggest that TB should be excluded in patients from endemic area presenting with abdominal masses. All patients received standard anti-tuberculous medication for an average duration of 7.4 months. The outcome was excellent with 88%% achieving complete response. Adjunctive corticosteroids were not used, and none of the patients had a surgical complication. CONCLUSION: The diagnosis of ATB is challenging. It can mimic inflammatory bowel disease in young populations and malignancy in middle-aged and elderly population. For this reason, a high index of suspicion with prompt treatment is required to improve the prognosis and prevent complications.

Isolation and deisolation of patients admitted with presumptive pulmonary tuberculosis. Can it be shortened?

OBJECTIVES: To determine the ideal number of sputum acid-fast bacilli (AFB) smears and polymerase chain reaction (PCR) required for discontinuing TB isolation among patients with suspected pulmonary TB.  Methods: This was a single-center, record-based retrospective study of all admitted patients diagnosed with culture-proven pulmonary TB between 2010 and 2018. The study was conducted at Prince Sultan Military Medical City (PSMMC) in Riyadh, Saudi Arabia, a large tertiary care center consisting of 1,200 beds. Data were obtained from our TB notification records. Patients with smear-positive TB were investigated. Only the first 3 sputum smears for AFB were included in the analysis. The  PCR results for Mycobacterium tuberculosis (MTB) were also included in the study. The incremental yield of the second and third smears was assessed.  Results: Overall, 240 patients were MTB-culture positive. A total of 126 (52.5%) patients were smear and culture positive, whereas 114 were culture positive but smear negative. Of 126 patients who were AFB smear positive, 98 (77.8%) were detected in the first specimen, 13 (10.3%) in the second specimen, and only 9 (7.1%) in the third specimen. Polymerase chain reaction for MTB was positive in 122 (96.8%) smear-positive patients. Four patients did not undergo a PCR test.  Conclusion:  A single Xpert MTB/resistance to rifampicin test detected all smear-positive patients, whereas the third smear did not significantly contribute to MTB isolation.

Demographic risk factors for extra-pulmonary tuberculosis among adolescents and adults in Saudi Arabia.

Despite low infectious potential of extrapulmonary tuberculosis (EPTB), it poses significant clinical challenges in terms of diagnosis and treatment monitoring. Understanding the main demographical risk factors for disease characteristics of EPTB plays a crucial role in speeding up diagnosis process and improving overall clinical experience. The aim of this study was to investigate the main demographical and clinical risk factors for EPTB among adults and adolescents for the first time in Saudi Arabia. A cross-sectional multicenter study was carried out on a collection of 902 extrapulmonary Mycobacterium tuberculosis complex (MTBC) isolates with demographical and clinical data. All isolates were subjected to spoligotyping and 24-loci based MIRU-VNTR typing. The association between two potential variables was assessed using odd ratios (OR) calculations. Independent risk factors for EPTB and diseases characteristics of EPTB were identified using multivariate regression model analyses. Gender was found to be significantly associated with lymph node, gastrointestinal, central nervous system and urogenital TB. Lymph node TB showed statistical association to age group below 25 years, non-Saudis and South East Asian ethnicity. While gastrointestinal TB demonstrated an association with patients above 60 years old, and Saudis. Multivariate analysis showed that gender is an independent risk factor to urogenital TB (p 0.03) and lymph node TB (p 0.005). On the other hands, South Asian (p 0.01) and South East Asian (p 0.03) ethnicities were both identified as independent risk factors significantly associated with EPTB. MTBC lineages, site of infections, gender, HIV and smear positivity showed no significant association. Nationwide qualitative-studies are highly warranted in the future to further understand the main demographic risk factors for disease characteristics of EPTB.

Miliary tuberculosis presenting as bilateral superficial femoral artery mycotic aneurysm in an immunocompetent patient.

Mycotic tuberculous aneurysm is extremely rare. The aorta is the main affected artery however; iliac and less commonly femoral arteries can also be affected. In 75% of the cases a contagious focus leads to infection through erosion of the vessel wall; on the other hand direct seeding of the blood vessel wall via the vasa vasorum may occur in 25%. In a large number of patients it may be a manifestation of miliary tuberculosis. In this case report we describe an immunocompetent patient who presented with bilateral superficial femoral artery aneurysms, followed by bilateral testicular swellings and inferior mesenteric artery aneurysm, as a presentation of military tuberculosis. Early diagnosis of such patients is essential for initiation of both medical and surgical treatment in order to avoid catastrophic outcome of rupture and bleeding.

Clinical respiratory infections and pneumonia during the Hajj pilgrimage: A systematic review.

BACKGROUND: The Islamic Hajj pilgrimage to Mecca is one of the world's largest annual mass gatherings. Inevitable overcrowding during the pilgrims' stay greatly increases the risk of acquiring and spreading infectious diseases, especially respiratory diseases. METHOD: The MEDLINE/PubMed and Scopus databases were searched for all relevant papers published prior to February 2018 that evaluated the prevalence of clinical symptoms of respiratory infections, including pneumonia, among Hajj pilgrims, as well as their influenza and pneumococcal vaccination status. RESULTS: A total of 61 papers were included in the review. Both cohort- and hospital-based studies provide complementary data, and both are therefore necessary to provide a complete picture of the total burden of respiratory diseases during the Hajj. Respiratory symptoms have been common among Hajj pilgrims over the last 15 years. In cohorts of pilgrims, cough ranged from 1.9% to 91.5%. However, the prevalence rates of the most common symptoms (cough, sore throat, and subjective fever) of influenza-like illness (ILI) varied widely across the included studies. These studies have shown variable results, with overall rates of ILI ranging from 8% to 78.2%. These differences might result from differences in study design, study period, and rates of vaccination against seasonal influenza that ranged from 1.1% to 100% among study participants. Moreover, the definition of ILI was inconsistent across studies. In hospitalized Hajj pilgrims, the prevalence of pneumonia, that remains a major concern in critically ill patients, ranged from 0.2% to 54.8%. CONCLUSIONS: Large multinational follow-up studies are recommended for clinic-based syndromic surveillance, in conjunction with microbiological surveillance. Matched cohorts ensure better comparability across studies. However, study design and data collection procedures should be standardized to facilitate reporting and to achieve comparability between studies. Furthermore, the definition of ILI, and of most common symptoms used to define respiratory infections (e.g., upper respiratory tract infection), need to be precisely defined and consistently used. Future studies need to address potential effect of influenza and pneumococcal vaccine in the context of the Hajj pilgrimage.

Proportion of adult community-acquired pneumonia cases attributable to Streptococcus pneumoniae among Hajj pilgrims in 2016.

BACKGROUND: The Hajj mass gathering is a risk for pneumococcal disease. This study was performed to evaluate the proportion of adult community-acquired pneumonia (CAP) cases attributable to Streptococcus pneumoniae among Hajj pilgrims in 2016. To add sensitivity to etiological attribution, a urine antigen test was used in addition to culture-based methods. METHODS: Adult subjects hospitalized with X-ray-confirmed CAP were enrolled prospectively from all general hospitals designated to treat Hajj pilgrims in the holy cities of Mecca and Medina. Patients were treated according to local standard of care and administered the BinaxNow S. pneumoniae urine antigen test. RESULTS: From August 23 to September 23, 2016, a total of 266 patients with CAP were enrolled in the study, 70.6% of whom were admitted to hospitals in Mecca; 53% of the cases were admitted after the peak of Hajj. Patients originated from 43 countries. Their mean age was 65.3 years and the male to female ratio was 2:1. Just over 36% of the cases had diabetes, 10% declared that they were smokers, and 45.4% of cases were treated in the intensive care unit (ICU). The overall case-fatality rate was 10.1%, but was higher among those treated in the ICU and in those with invasive disease. The proportion of CAP cases positive for S. pneumoniae, based on culture or urine antigen test, was 18.0% (95% confidence interval 13.9-23.1%). CONCLUSIONS: CAP during Hajj has an important clinical impact. A proportion of CAP cases among Hajj pilgrims were attributable to S. pneumoniae, a pathogen for which vaccines are available. Additional studies to determine the serotypes causing pneumococcal disease could further inform vaccine policy for Hajj pilgrims.

Narcolepsy in Saudi patients before and after the 2009 H1N1 vaccination. The experience of 2 referral centers.

OBJECTIVES: To assess the number of Saudi patients diagnosed with narcolepsy in 2 tertiary centers before and after the introduction of the 2009 A(H1N1)pdm09 vaccine.  Methods: We started collecting data after the first international report of an association between the A(H1N1)pdm09 vaccine and narcolepsy between January 2010 and December 2016. All patients diagnosed with narcolepsy after 2009 were included and data were collected for 7 years to account for any possible delays in the diagnosis of narcolepsy.  Results: One-hundred and seventy-three patients with narcolepsy were identified. The majority (144 patients, 83%) had symptom onset before June 2009. Only 29 patients (17%) had symptom onset after 2009. No difference in the annual number of narcolepsy cases was found  before and after 2009. Conclusion: Based on data obtained from 2 tertiary care sleep disorders center, there was no increase in the number of cases of narcolepsy among Saudis following the introduction of the influenza A(H1N1)pdm09 vaccination.

Viral Shedding and Antibody Response in 37 Patients With Middle East Respiratory Syndrome Coronavirus Infection.

BACKGROUND: The Middle East respiratory syndrome (MERS) coronavirus causes isolated cases and outbreaks of severe respiratory disease. Essential features of the natural history of disease are poorly understood. METHODS: We studied 37 adult patients infected with MERS coronavirus for viral load in the lower and upper respiratory tracts (LRT and URT, respectively), blood, stool, and urine. Antibodies and serum neutralizing activities were determined over the course of disease. RESULTS: One hundred ninety-nine LRT samples collected during the 3 weeks following diagnosis yielded virus RNA in 93% of tests. Average (maximum) viral loads were 5 × 10(6) (6 × 10(10)) copies/mL. Viral loads (positive detection frequencies) in 84 URT samples were 1.9 × 10(4) copies/mL (47.6%). Thirty-three percent of all 108 serum samples tested yielded viral RNA. Only 14.6% of stool and 2.4% of urine samples yielded viral RNA. All seroconversions occurred during the first 2 weeks after diagnosis, which corresponds to the second and third week after symptom onset. Immunoglobulin M detection provided no advantage in sensitivity over immunoglobulin G (IgG) detection. All surviving patients, but only slightly more than half of all fatal cases, produced IgG and neutralizing antibodies. The levels of IgG and neutralizing antibodies were weakly and inversely correlated with LRT viral loads. Presence of antibodies did not lead to the elimination of virus from LRT. CONCLUSIONS: The timing and intensity of respiratory viral shedding in patients with MERS closely matches that of those with severe acute respiratory syndrome. Blood viral RNA does not seem to be infectious. Extrapulmonary loci of virus replication seem possible. Neutralizing antibodies do not suffice to clear the infection.

Infectious Middle East Respiratory Syndrome Coronavirus Excretion and Serotype Variability Based on Live Virus Isolates from Patients in Saudi Arabia.

The newly emerged Middle East respiratory syndrome coronavirus (MERS-CoV) has infected at least 1,082 people, including 439 fatalities. So far, no empirical virus isolation study has been done to elucidate infectious virus secretion or serotype variability. Here, we used 51 respiratory samples from 32 patients with confirmed MERS-CoV infection for virus isolation in Vero B4 and Caco-2 cells. We found Caco-2 cells to significantly enhance isolation success over routinely used Vero cells. Isolation success correlated with viral RNA concentration and time after diagnosis as well as with the amount of IgA antibodies secreted in respiratory samples used for isolation. Results from plaque reduction neutralization assays using a representative range of serum samples and virus isolates suggested that all circulating human MERS-CoV strains represent one single serotype. The choice of prototype strain is not likely to influence the success of candidate MERS-CoV vaccines. However, vaccine formulations should be evaluated for their potential to induce IgA.

Presence of Middle East respiratory syndrome coronavirus antibodies in Saudi Arabia: a nationwide, cross-sectional, serological study.

BACKGROUND: Scientific evidence suggests that dromedary camels are the intermediary host for the Middle East respiratory syndrome coronavirus (MERS-CoV). However, the actual number of infections in people who have had contact with camels is unknown and most index patients cannot recall any such contact. We aimed to do a nationwide serosurvey in Saudi Arabia to establish the prevalence of MERS-CoV antibodies, both in the general population and in populations of individuals who have maximum exposure to camels. METHODS: In the cross-sectional serosurvey, we tested human serum samples obtained from healthy individuals older than 15 years who attended primary health-care centres or participated in a national burden-of-disease study in all 13 provinces of Saudi Arabia. Additionally, we tested serum samples from shepherds and abattoir workers with occupational exposure to camels. Samples were screened by recombinant ELISA and MERS-CoV seropositivity was confirmed by recombinant immunofluorescence and plaque reduction neutralisation tests. We used two-tailed Mann Whitney U exact tests, χ(2), and Fisher's exact tests to analyse the data. FINDINGS: Between Dec 1, 2012, and Dec 1, 2013, we obtained individual serum samples from 10,009 individuals. Anti-MERS-CoV antibodies were confirmed in 15 (0·15%; 95% CI 0·09-0·24) of 10,009 people in six of the 13 provinces. The mean age of seropositive individuals was significantly younger than that of patients with reported, laboratory-confirmed, primary Middle Eastern respiratory syndrome (43·5 years [SD 17·3] vs 53·8 years [17·5]; p=0·008). Men had a higher antibody prevalence than did women (11 [0·25%] of 4341 vs two [0·05%] of 4378; p=0·028) and antibody prevalence was significantly higher in central versus coastal provinces (14 [0·26%] of 5479 vs one [0·02%] of 4529; p=0·003). Compared with the general population, seroprevalence of MERS-CoV antibodies was significantly increased by 15 times in shepherds (two [2·3%] of 87, p=0·0004) and by 23 times in slaughterhouse workers (five [3·6%] of 140; p<0·0001). INTERPRETATION: Seroprevalence of MERS-CoV antibodies was significantly higher in camel-exposed individuals than in the general population. By simple multiplication, a projected 44,951 (95% CI 26,971-71,922) individuals older than 15 years might be seropositive for MERS-CoV in Saudi Arabia. These individuals might be the source of infection for patients with confirmed MERS who had no previous exposure to camels. FUNDING: European Union, German Centre for Infection Research, Federal Ministry of Education and Research, German Research Council, and Ministry of Health of Saudi Arabia.

High dose intravenous colistin methanesulfonate therapy is associated with high rates of nephrotoxicity; a prospective cohort study from Saudi Arabia.

BACKGROUND: Nephrotoxicity is an important adverse effect of colistin methanesulfonate (CMS) therapy. No data exist on rates and risk factors for colistin-related nephrotoxicity in Saudi Arabia (SA). We conducted a prospective cohort study to identify rates and risk factors for CMS nephrotoxicity in our patient population. METHODS: We prospectively included adult patients who received ≥48 hours of intravenous CMS therapy. Pregnant patients and those on renal replacement were excluded. Patients received 9 million units (mU) loading dose followed by 3 mU 8 hourly. In renal impairment, CMS dosing was adjusted according to calculated creatinine clearance (CrCl). Nephrotoxicity was defined as per RIFLE criteria (Risk, Injury, Failure, Loss and End-stage renal disease). Statistical analysis was performed using SPSS version 20.0 (IBM, Armonk, New York, USA). The study was approved by the institution's Research Ethics Committee. RESULTS: A total of 67 patients were included in the study. Mean (±standard deviation) age was 57.5 (±24.0) years, Charlson Co-morbidity Score 2.88 (±2.39), CrCl 133.60 (±92.54) mL/min and serum albumin 28.65 (±4.45) g/L. Mean CMS dose was 0.11 (±0.04) mU/kg/day and mean total CMS dose received was 101.21 (±47.37) mU. Fifty-one (76.1%) patients developed RIFLE-defined nephrotoxicity. Mean total CMS dose and duration of therapy before onset of nephrotoxicity were 66.71 (±43.45) mU and 8.70 (±6.70) days, respectively. In bivariate analysis, patients with nephrotoxicity were significantly older (P 0.013) and had lower baseline serum albumin (P 0.008). Multivariate logistic regression identified serum albumin [odds ratio (OR) 0.72; 95% confidence interval (CI) 0.57-0.93; P 0.010] and intensive care admission (OR 16.38; 95% CI 1.37-195.55; P 0.027) as independent risk factors for CMS nephrotoxicity. CONCLUSIONS: High dose intravenous CMS therapy is associated with high rates of nephrotoxicity in SA. Independent risk factors for colistin nephrotoxicity were baseline hypoalbuminemia and intensive care admission.